Question

怎样使用matlab解下面的代数方程？急急。。。。。

syms a b c d e;
2*b^2=a^2+c^2+d^2-d*((4*r^2-y^2)^(1/2)*cos(e)+y*sin(e))-2*c*d*((r^2-d^2*(cos(e))^2)^(1/2)*cos(e)+d*cos(e)*sin(e))/r+c*((4*r^2-y^2)^(1/2)* (r^2-d^2*(cos(e))^2)^(1/2)+y*d*cos(e)) ;
Solve(y,r)
我想将上面的方程写成y=f(r)的形式，其他的都安已知量计算。但是为什么总出错呢？请教那位大哥帮小弟解一下。谢谢了
我的目的是将此方程化简写成y=f(r)的形式。谢谢大家帮忙解决一下谢谢了

Answer 1

这个答案不就是y=f(r)的形式吗？只是比较长而已。。。
可以这样解决：
syms a b c d e;
solve('2*b^2=a^2+c^2+d^2-d*((4*r^2-y^2)^(1/2)*cos(e)+y*sin(e))-2*c*d*((r^2-d^2*(cos(e))^2)^(1/2)*cos(e)+d*cos(e)*sin(e))/r+c*((4*r^2-y^2)^(1/2)* (r^2-d^2*(cos(e))^2)^(1/2)+y*d*cos(e))')
Warning: Warning, solutions may have been lost

ans =

-(-2*b^2*r+a^2*r+c^2*r+d^2*r+d*(-2*c^2*r^2*d*cos(e)+c^3*r*(r^2-d^2*cos(e)^2)^(1/2)+2*b^2*r*d*cos(e)-d^3*r*cos(e)+a^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)+d^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)-a^2*r*d*cos(e)-2*b^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)-c^2*r*d*cos(e)-2*d^3*c*sin(e)^3+2*d^3*c*sin(e)+2*d^2*c*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-2*c^2*d^2*cos(e)*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+2*cos(e)^3*c^2*d^3-(-4*d^6*c^2*cos(e)^6-d^2*c^4*r^2-d^2*a^4*r^2+4*d^4*b^2*r^2-4*d^2*b^4*r^2-2*d^2*a^2*r^2*c^2-2*d^4*c^2*r^2-2*d^4*a^2*r^2+4*d^2*b^2*r^2*c^2+2*d^4*r^2*cos(e)^2*a^2+4*d^2*b^2*r^2*a^2-4*c^4*r*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+4*c^4*r*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)+8*c^4*r^2*d^3*cos(e)^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)-8*c^4*r^2*d^4*cos(e)^4+4*d^6*c^2*sin(e)^2+24*b^2*r*d^3*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+d^6*r^2*cos(e)^2+4*d^6*r*cos(e)*c*sin(e)^3-4*b^2*r^2*d^4*cos(e)^2-4*b^2*r^2*d^2*cos(e)^2*a^2-4*d^5*r*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)-4*b^2*r^2*d^2*cos(e)^2*c^2-8*b^2*r*d^4*cos(e)*c*sin(e)^3+4*b^4*r^2*d^2*cos(e)^2+8*b^2*r*d^3*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)-2*d^4*r^2*cos(e)^2*c^2+4*c^5*r*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3-4*a^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+4*a^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)+8*r^2*c^4*d^4*sin(e)^4-12*d^5*r*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+2*a^2*r^2*d^2*cos(e)^2*c^2+4*a^2*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3+a^4*r^2*d^2*cos(e)^2+4*d^5*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)+4*d^5*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3-4*d^5*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+4*a^2*r*d^4*cos(e)*c*sin(e)^3+c^4*r^2*d^2*cos(e)^2-4*a^2*r*d^3*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)+8*d^5*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^5-12*a^2*r*d^3*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*cos(e)^6*c^4*d^6-8*b^2*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3-4*c^3*r*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)+4*c^3*r*d^4*cos(e)*sin(e)^3+4*r^6*c^4*d^2*cos(e)^2+4*d^6*c^2*sin(e)^6-12*c^4*r*d^3*cos(e)^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*b^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+8*d^6*c^3*sin(e)^3*cos(e)^3-8*b^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)-32*d^6*c^3*sin(e)*cos(e)^3-8*c*d^2*cos(e)*sin(e)*b^2*r^2*a^2+12*d^6*c^2*cos(e)^2-8*r^2*c^4*d^3*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)-8*c^4*d^5*cos(e)^4*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*r^2*c^4*d^3*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+8*d^5*c^3*sin(e)^2*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)-24*d^5*c^3*sin(e)^4*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*d^5*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-8*d^5*c^2*sin(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-d^6*c^2*r^2*cos(e)^2-4*r^6*c^2*d^2*cos(e)^2-c^6*r^2*d^2*cos(e)^2+4*d^4*c^2*cos(e)^4*r^2+8*d^6*c^3*cos(e)^5*sin(e)+10*r^2*c^4*d^4*cos(e)^2-4*c^4*d^6*cos(e)^4*sin(e)^2-8*c^3*d^2*cos(e)*sin(e)*b^2*r^2-8*c^3*d^4*cos(e)^3*sin(e)*r^4-8*r^6*c^3*d^2*sin(e)*cos(e)-8*c*d^4*cos(e)*sin(e)*b^2*r^2+8*d^5*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+8*c*d^2*cos(e)*sin(e)*b^4*r^2-24*c^3*d^5*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)+2*c*d^2*cos(e)*sin(e)*a^4*r^2+16*c^3*d^5*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*c*d^4*cos(e)*sin(e)*a^2*r^2-8*c^2*d^4*cos(e)^2*sin(e)^2*a^2*r-16*c^3*d^6*cos(e)*sin(e)^5+16*c^2*d^4*cos(e)^2*sin(e)^2*b^2*r+16*c^3*d^6*cos(e)*sin(e)+8*c*d^4*cos(e)^3*sin(e)*r^4+2*c*d^6*cos(e)*sin(e)*r^2+2*c^5*d^2*cos(e)*sin(e)*r^2+16*c^2*d^4*cos(e)^2*sin(e)^2*r^4+4*c^3*d^2*cos(e)*sin(e)*a^2*r^2+4*d^4*r^4*c^2*cos(e)^2-8*c^3*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*r^4-8*c^2*d^6*cos(e)^2*sin(e)^2*r-16*c*d^4*cos(e)*sin(e)*r^4-8*c^4*d^4*cos(e)^2*sin(e)^2*r-4*b^4*r^2*c^2*d^2*cos(e)^2-8*d^3*b^2*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*c*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*r^4+4*d^5*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*d^3*c^3*r*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)-8*c*d^3*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)*r^4+16*c^2*d^3*cos(e)^2*(r^2-d^2*cos(e)^2)^(1/2)*r^4*sin(e)-8*d^5*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)-8*c^3*r^2*d^4*cos(e)*sin(e)^3+12*c^3*r^2*d^4*cos(e)*sin(e)-4*d^4*r^4*cos(e)^2+4*d^3*a^2*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*a^2*r^2*c^2*b^2*d^2*cos(e)^2+4*a^2*r*c^3*d^4*cos(e)^3*sin(e)-a^4*r^2*c^2*d^2*cos(e)^2+4*c^5*r*d^4*cos(e)^3*sin(e)-8*r^2*c^4*d^4+4*r^6*c^2*d^2+4*c^4*r^2*b^2*d^2*cos(e)^2-2*d^4*a^2*r^2*c^2*cos(e)^2+4*d^4*b^2*r^2*c^2*cos(e)^2-2*c^4*r^2*a^2*d^2*cos(e)^2+4*d^4*r^4+4*c^4*d^4*cos(e)^2*sin(e)^2*r^2+4*c^3*r*d^6*cos(e)^3*sin(e)-8*d^6*c^2-8*b^2*r*c^3*d^4*cos(e)^3*sin(e)-d^6*r^2)^(1/2))/(r^2*c^2-2*c*d^2*cos(e)*sin(e)-2*c*d*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+d^2)*cos(e)-2*c*d*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)-2*c*d^2*cos(e)*sin(e)-c*(-2*c^2*r^2*d*cos(e)+c^3*r*(r^2-d^2*cos(e)^2)^(1/2)+2*b^2*r*d*cos(e)-d^3*r*cos(e)+a^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)+d^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)-a^2*r*d*cos(e)-2*b^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)-c^2*r*d*cos(e)-2*d^3*c*sin(e)^3+2*d^3*c*sin(e)+2*d^2*c*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-2*c^2*d^2*cos(e)*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+2*cos(e)^3*c^2*d^3-(-4*d^6*c^2*cos(e)^6-d^2*c^4*r^2-d^2*a^4*r^2+4*d^4*b^2*r^2-4*d^2*b^4*r^2-2*d^2*a^2*r^2*c^2-2*d^4*c^2*r^2-2*d^4*a^2*r^2+4*d^2*b^2*r^2*c^2+2*d^4*r^2*cos(e)^2*a^2+4*d^2*b^2*r^2*a^2-4*c^4*r*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+4*c^4*r*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)+8*c^4*r^2*d^3*cos(e)^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)-8*c^4*r^2*d^4*cos(e)^4+4*d^6*c^2*sin(e)^2+24*b^2*r*d^3*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+d^6*r^2*cos(e)^2+4*d^6*r*cos(e)*c*sin(e)^3-4*b^2*r^2*d^4*cos(e)^2-4*b^2*r^2*d^2*cos(e)^2*a^2-4*d^5*r*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)-4*b^2*r^2*d^2*cos(e)^2*c^2-8*b^2*r*d^4*cos(e)*c*sin(e)^3+4*b^4*r^2*d^2*cos(e)^2+8*b^2*r*d^3*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)-2*d^4*r^2*cos(e)^2*c^2+4*c^5*r*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3-4*a^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+4*a^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)+8*r^2*c^4*d^4*sin(e)^4-12*d^5*r*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+2*a^2*r^2*d^2*cos(e)^2*c^2+4*a^2*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3+a^4*r^2*d^2*cos(e)^2+4*d^5*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)+4*d^5*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3-4*d^5*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+4*a^2*r*d^4*cos(e)*c*sin(e)^3+c^4*r^2*d^2*cos(e)^2-4*a^2*r*d^3*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)+8*d^5*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^5-12*a^2*r*d^3*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*cos(e)^6*c^4*d^6-8*b^2*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3-4*c^3*r*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)+4*c^3*r*d^4*cos(e)*sin(e)^3+4*r^6*c^4*d^2*cos(e)^2+4*d^6*c^2*sin(e)^6-12*c^4*r*d^3*cos(e)^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*b^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+8*d^6*c^3*sin(e)^3*cos(e)^3-8*b^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)-32*d^6*c^3*sin(e)*cos(e)^3-8*c*d^2*cos(e)*sin(e)*b^2*r^2*a^2+12*d^6*c^2*cos(e)^2-8*r^2*c^4*d^3*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)-8*c^4*d^5*cos(e)^4*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*r^2*c^4*d^3*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+8*d^5*c^3*sin(e)^2*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)-24*d^5*c^3*sin(e)^4*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*d^5*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-8*d^5*c^2*sin(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-d^6*c^2*r^2*cos(e)^2-4*r^6*c^2*d^2*cos(e)^2-c^6*r^2*d^2*cos(e)^2+4*d^4*c^2*cos(e)^4*r^2+8*d^6*c^3*cos(e)^5*sin(e)+10*r^2*c^4*d^4*cos(e)^2-4*c^4*d^6*cos(e)^4*sin(e)^2-8*c^3*d^2*cos(e)*sin(e)*b^2*r^2-8*c^3*d^4*cos(e)^3*sin(e)*r^4-8*r^6*c^3*d^2*sin(e)*cos(e)-8*c*d^4*cos(e)*sin(e)*b^2*r^2+8*d^5*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+8*c*d^2*cos(e)*sin(e)*b^4*r^2-24*c^3*d^5*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)+2*c*d^2*cos(e)*sin(e)*a^4*r^2+16*c^3*d^5*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*c*d^4*cos(e)*sin(e)*a^2*r^2-8*c^2*d^4*cos(e)^2*sin(e)^2*a^2*r-16*c^3*d^6*cos(e)*sin(e)^5+16*c^2*d^4*cos(e)^2*sin(e)^2*b^2*r+16*c^3*d^6*cos(e)*sin(e)+8*c*d^4*cos(e)^3*sin(e)*r^4+2*c*d^6*cos(e)*sin(e)*r^2+2*c^5*d^2*cos(e)*sin(e)*r^2+16*c^2*d^4*cos(e)^2*sin(e)^2*r^4+4*c^3*d^2*cos(e)*sin(e)*a^2*r^2+4*d^4*r^4*c^2*cos(e)^2-8*c^3*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*r^4-8*c^2*d^6*cos(e)^2*sin(e)^2*r-16*c*d^4*cos(e)*sin(e)*r^4-8*c^4*d^4*cos(e)^2*sin(e)^2*r-4*b^4*r^2*c^2*d^2*cos(e)^2-8*d^3*b^2*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*c*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*r^4+4*d^5*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*d^3*c^3*r*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)-8*c*d^3*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)*r^4+16*c^2*d^3*cos(e)^2*(r^2-d^2*cos(e)^2)^(1/2)*r^4*sin(e)-8*d^5*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)-8*c^3*r^2*d^4*cos(e)*sin(e)^3+12*c^3*r^2*d^4*cos(e)*sin(e)-4*d^4*r^4*cos(e)^2+4*d^3*a^2*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*a^2*r^2*c^2*b^2*d^2*cos(e)^2+4*a^2*r*c^3*d^4*cos(e)^3*sin(e)-a^4*r^2*c^2*d^2*cos(e)^2+4*c^5*r*d^4*cos(e)^3*sin(e)-8*r^2*c^4*d^4+4*r^6*c^2*d^2+4*c^4*r^2*b^2*d^2*cos(e)^2-2*d^4*a^2*r^2*c^2*cos(e)^2+4*d^4*b^2*r^2*c^2*cos(e)^2-2*c^4*r^2*a^2*d^2*cos(e)^2+4*d^4*r^4+4*c^4*d^4*cos(e)^2*sin(e)^2*r^2+4*c^3*r*d^6*cos(e)^3*sin(e)-8*d^6*c^2-8*b^2*r*c^3*d^4*cos(e)^3*sin(e)-d^6*r^2)^(1/2))/(r^2*c^2-2*c*d^2*cos(e)*sin(e)-2*c*d*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+d^2)*(r^2-d^2*cos(e)^2)^(1/2))/d/r/(-sin(e)+c*cos(e))
-(-2*b^2*r+a^2*r+c^2*r+d^2*r+d*(-2*c^2*r^2*d*cos(e)+c^3*r*(r^2-d^2*cos(e)^2)^(1/2)+2*b^2*r*d*cos(e)-d^3*r*cos(e)+a^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)+d^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)-a^2*r*d*cos(e)-2*b^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)-c^2*r*d*cos(e)-2*d^3*c*sin(e)^3+2*d^3*c*sin(e)+2*d^2*c*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-2*c^2*d^2*cos(e)*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+2*cos(e)^3*c^2*d^3+(-4*d^6*c^2*cos(e)^6-d^2*c^4*r^2-d^2*a^4*r^2+4*d^4*b^2*r^2-4*d^2*b^4*r^2-2*d^2*a^2*r^2*c^2-2*d^4*c^2*r^2-2*d^4*a^2*r^2+4*d^2*b^2*r^2*c^2+2*d^4*r^2*cos(e)^2*a^2+4*d^2*b^2*r^2*a^2-4*c^4*r*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+4*c^4*r*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)+8*c^4*r^2*d^3*cos(e)^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)-8*c^4*r^2*d^4*cos(e)^4+4*d^6*c^2*sin(e)^2+24*b^2*r*d^3*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+d^6*r^2*cos(e)^2+4*d^6*r*cos(e)*c*sin(e)^3-4*b^2*r^2*d^4*cos(e)^2-4*b^2*r^2*d^2*cos(e)^2*a^2-4*d^5*r*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)-4*b^2*r^2*d^2*cos(e)^2*c^2-8*b^2*r*d^4*cos(e)*c*sin(e)^3+4*b^4*r^2*d^2*cos(e)^2+8*b^2*r*d^3*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)-2*d^4*r^2*cos(e)^2*c^2+4*c^5*r*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3-4*a^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+4*a^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)+8*r^2*c^4*d^4*sin(e)^4-12*d^5*r*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+2*a^2*r^2*d^2*cos(e)^2*c^2+4*a^2*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3+a^4*r^2*d^2*cos(e)^2+4*d^5*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)+4*d^5*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3-4*d^5*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+4*a^2*r*d^4*cos(e)*c*sin(e)^3+c^4*r^2*d^2*cos(e)^2-4*a^2*r*d^3*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)+8*d^5*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^5-12*a^2*r*d^3*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*cos(e)^6*c^4*d^6-8*b^2*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3-4*c^3*r*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)+4*c^3*r*d^4*cos(e)*sin(e)^3+4*r^6*c^4*d^2*cos(e)^2+4*d^6*c^2*sin(e)^6-12*c^4*r*d^3*cos(e)^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*b^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+8*d^6*c^3*sin(e)^3*cos(e)^3-8*b^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)-32*d^6*c^3*sin(e)*cos(e)^3-8*c*d^2*cos(e)*sin(e)*b^2*r^2*a^2+12*d^6*c^2*cos(e)^2-8*r^2*c^4*d^3*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)-8*c^4*d^5*cos(e)^4*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*r^2*c^4*d^3*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+8*d^5*c^3*sin(e)^2*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)-24*d^5*c^3*sin(e)^4*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*d^5*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-8*d^5*c^2*sin(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-d^6*c^2*r^2*cos(e)^2-4*r^6*c^2*d^2*cos(e)^2-c^6*r^2*d^2*cos(e)^2+4*d^4*c^2*cos(e)^4*r^2+8*d^6*c^3*cos(e)^5*sin(e)+10*r^2*c^4*d^4*cos(e)^2-4*c^4*d^6*cos(e)^4*sin(e)^2-8*c^3*d^2*cos(e)*sin(e)*b^2*r^2-8*c^3*d^4*cos(e)^3*sin(e)*r^4-8*r^6*c^3*d^2*sin(e)*cos(e)-8*c*d^4*cos(e)*sin(e)*b^2*r^2+8*d^5*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+8*c*d^2*cos(e)*sin(e)*b^4*r^2-24*c^3*d^5*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)+2*c*d^2*cos(e)*sin(e)*a^4*r^2+16*c^3*d^5*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*c*d^4*cos(e)*sin(e)*a^2*r^2-8*c^2*d^4*cos(e)^2*sin(e)^2*a^2*r-16*c^3*d^6*cos(e)*sin(e)^5+16*c^2*d^4*cos(e)^2*sin(e)^2*b^2*r+16*c^3*d^6*cos(e)*sin(e)+8*c*d^4*cos(e)^3*sin(e)*r^4+2*c*d^6*cos(e)*sin(e)*r^2+2*c^5*d^2*cos(e)*sin(e)*r^2+16*c^2*d^4*cos(e)^2*sin(e)^2*r^4+4*c^3*d^2*cos(e)*sin(e)*a^2*r^2+4*d^4*r^4*c^2*cos(e)^2-8*c^3*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*r^4-8*c^2*d^6*cos(e)^2*sin(e)^2*r-16*c*d^4*cos(e)*sin(e)*r^4-8*c^4*d^4*cos(e)^2*sin(e)^2*r-4*b^4*r^2*c^2*d^2*cos(e)^2-8*d^3*b^2*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*c*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*r^4+4*d^5*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*d^3*c^3*r*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)-8*c*d^3*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)*r^4+16*c^2*d^3*cos(e)^2*(r^2-d^2*cos(e)^2)^(1/2)*r^4*sin(e)-8*d^5*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)-8*c^3*r^2*d^4*cos(e)*sin(e)^3+12*c^3*r^2*d^4*cos(e)*sin(e)-4*d^4*r^4*cos(e)^2+4*d^3*a^2*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*a^2*r^2*c^2*b^2*d^2*cos(e)^2+4*a^2*r*c^3*d^4*cos(e)^3*sin(e)-a^4*r^2*c^2*d^2*cos(e)^2+4*c^5*r*d^4*cos(e)^3*sin(e)-8*r^2*c^4*d^4+4*r^6*c^2*d^2+4*c^4*r^2*b^2*d^2*cos(e)^2-2*d^4*a^2*r^2*c^2*cos(e)^2+4*d^4*b^2*r^2*c^2*cos(e)^2-2*c^4*r^2*a^2*d^2*cos(e)^2+4*d^4*r^4+4*c^4*d^4*cos(e)^2*sin(e)^2*r^2+4*c^3*r*d^6*cos(e)^3*sin(e)-8*d^6*c^2-8*b^2*r*c^3*d^4*cos(e)^3*sin(e)-d^6*r^2)^(1/2))/(r^2*c^2-2*c*d^2*cos(e)*sin(e)-2*c*d*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+d^2)*cos(e)-2*c*d*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)-2*c*d^2*cos(e)*sin(e)-c*(-2*c^2*r^2*d*cos(e)+c^3*r*(r^2-d^2*cos(e)^2)^(1/2)+2*b^2*r*d*cos(e)-d^3*r*cos(e)+a^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)+d^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)-a^2*r*d*cos(e)-2*b^2*r*c*(r^2-d^2*cos(e)^2)^(1/2)-c^2*r*d*cos(e)-2*d^3*c*sin(e)^3+2*d^3*c*sin(e)+2*d^2*c*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-2*c^2*d^2*cos(e)*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+2*cos(e)^3*c^2*d^3+(-4*d^6*c^2*cos(e)^6-d^2*c^4*r^2-d^2*a^4*r^2+4*d^4*b^2*r^2-4*d^2*b^4*r^2-2*d^2*a^2*r^2*c^2-2*d^4*c^2*r^2-2*d^4*a^2*r^2+4*d^2*b^2*r^2*c^2+2*d^4*r^2*cos(e)^2*a^2+4*d^2*b^2*r^2*a^2-4*c^4*r*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+4*c^4*r*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)+8*c^4*r^2*d^3*cos(e)^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)-8*c^4*r^2*d^4*cos(e)^4+4*d^6*c^2*sin(e)^2+24*b^2*r*d^3*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+d^6*r^2*cos(e)^2+4*d^6*r*cos(e)*c*sin(e)^3-4*b^2*r^2*d^4*cos(e)^2-4*b^2*r^2*d^2*cos(e)^2*a^2-4*d^5*r*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)-4*b^2*r^2*d^2*cos(e)^2*c^2-8*b^2*r*d^4*cos(e)*c*sin(e)^3+4*b^4*r^2*d^2*cos(e)^2+8*b^2*r*d^3*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)-2*d^4*r^2*cos(e)^2*c^2+4*c^5*r*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3-4*a^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+4*a^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)+8*r^2*c^4*d^4*sin(e)^4-12*d^5*r*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+2*a^2*r^2*d^2*cos(e)^2*c^2+4*a^2*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3+a^4*r^2*d^2*cos(e)^2+4*d^5*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)+4*d^5*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3-4*d^5*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+4*a^2*r*d^4*cos(e)*c*sin(e)^3+c^4*r^2*d^2*cos(e)^2-4*a^2*r*d^3*cos(e)^3*c*(r^2-d^2*cos(e)^2)^(1/2)+8*d^5*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^5-12*a^2*r*d^3*cos(e)^2*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*cos(e)^6*c^4*d^6-8*b^2*r*c^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^3*d^3-4*c^3*r*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)+4*c^3*r*d^4*cos(e)*sin(e)^3+4*r^6*c^4*d^2*cos(e)^2+4*d^6*c^2*sin(e)^6-12*c^4*r*d^3*cos(e)^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*b^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)^3+8*d^6*c^3*sin(e)^3*cos(e)^3-8*b^2*r*c^2*(r^2-d^2*cos(e)^2)^(1/2)*d^3*sin(e)-32*d^6*c^3*sin(e)*cos(e)^3-8*c*d^2*cos(e)*sin(e)*b^2*r^2*a^2+12*d^6*c^2*cos(e)^2-8*r^2*c^4*d^3*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)-8*c^4*d^5*cos(e)^4*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*r^2*c^4*d^3*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+8*d^5*c^3*sin(e)^2*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)-24*d^5*c^3*sin(e)^4*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*d^5*c^2*sin(e)*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-8*d^5*c^2*sin(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*cos(e)^2-d^6*c^2*r^2*cos(e)^2-4*r^6*c^2*d^2*cos(e)^2-c^6*r^2*d^2*cos(e)^2+4*d^4*c^2*cos(e)^4*r^2+8*d^6*c^3*cos(e)^5*sin(e)+10*r^2*c^4*d^4*cos(e)^2-4*c^4*d^6*cos(e)^4*sin(e)^2-8*c^3*d^2*cos(e)*sin(e)*b^2*r^2-8*c^3*d^4*cos(e)^3*sin(e)*r^4-8*r^6*c^3*d^2*sin(e)*cos(e)-8*c*d^4*cos(e)*sin(e)*b^2*r^2+8*d^5*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)^3+8*c*d^2*cos(e)*sin(e)*b^4*r^2-24*c^3*d^5*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)+2*c*d^2*cos(e)*sin(e)*a^4*r^2+16*c^3*d^5*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*c*d^4*cos(e)*sin(e)*a^2*r^2-8*c^2*d^4*cos(e)^2*sin(e)^2*a^2*r-16*c^3*d^6*cos(e)*sin(e)^5+16*c^2*d^4*cos(e)^2*sin(e)^2*b^2*r+16*c^3*d^6*cos(e)*sin(e)+8*c*d^4*cos(e)^3*sin(e)*r^4+2*c*d^6*cos(e)*sin(e)*r^2+2*c^5*d^2*cos(e)*sin(e)*r^2+16*c^2*d^4*cos(e)^2*sin(e)^2*r^4+4*c^3*d^2*cos(e)*sin(e)*a^2*r^2+4*d^4*r^4*c^2*cos(e)^2-8*c^3*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*r^4-8*c^2*d^6*cos(e)^2*sin(e)^2*r-16*c*d^4*cos(e)*sin(e)*r^4-8*c^4*d^4*cos(e)^2*sin(e)^2*r-4*b^4*r^2*c^2*d^2*cos(e)^2-8*d^3*b^2*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+8*c*d^3*cos(e)^3*(r^2-d^2*cos(e)^2)^(1/2)*r^4+4*d^5*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*d^3*c^3*r*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)-8*c*d^3*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)*r^4+16*c^2*d^3*cos(e)^2*(r^2-d^2*cos(e)^2)^(1/2)*r^4*sin(e)-8*d^5*c^2*(r^2-d^2*cos(e)^2)^(1/2)*sin(e)-8*c^3*r^2*d^4*cos(e)*sin(e)^3+12*c^3*r^2*d^4*cos(e)*sin(e)-4*d^4*r^4*cos(e)^2+4*d^3*a^2*r*c*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+4*a^2*r^2*c^2*b^2*d^2*cos(e)^2+4*a^2*r*c^3*d^4*cos(e)^3*sin(e)-a^4*r^2*c^2*d^2*cos(e)^2+4*c^5*r*d^4*cos(e)^3*sin(e)-8*r^2*c^4*d^4+4*r^6*c^2*d^2+4*c^4*r^2*b^2*d^2*cos(e)^2-2*d^4*a^2*r^2*c^2*cos(e)^2+4*d^4*b^2*r^2*c^2*cos(e)^2-2*c^4*r^2*a^2*d^2*cos(e)^2+4*d^4*r^4+4*c^4*d^4*cos(e)^2*sin(e)^2*r^2+4*c^3*r*d^6*cos(e)^3*sin(e)-8*d^6*c^2-8*b^2*r*c^3*d^4*cos(e)^3*sin(e)-d^6*r^2)^(1/2))/(r^2*c^2-2*c*d^2*cos(e)*sin(e)-2*c*d*cos(e)*(r^2-d^2*cos(e)^2)^(1/2)+d^2)*(r^2-d^2*cos(e)^2)^(1/2))/d/r/(-sin(e)+c*cos(e))

我觉得你的目的不是解这个方程，不管怎样，告你怎么搞吧

Answer 2

y=solve('2*b^2=a^2+c^2+d^2-d*((4*r^2-y^2)^(1/2)*cos(e)+y*sin(e))-2*c*d*((r^2-d^2*(cos(e))^2)^(1/2)*cos(e)+d*cos(e)*sin(e))/r+c*((4*r^2-y^2)^(1/2)* (r^2-d^2*(cos(e))^2)^(1/2)+y*d*cos(e))','y')
这不就是y=f(r)的形式吗，还是2个解。

Answer 3

你应该也把y定义上，即：
syms a b c d e y；
然后你再试试。

Answer 4

把方程左边的挪到右边去
syms a b c d e y r;
f = -2*b^2 + a^2+c^2+d^2-d*((4*r^2-y^2)^(1/2)*cos(e)+y*sin(e))-2*c*d*((r^2-d^2*(cos(e))^2)^(1/2)*cos(e)+d*cos(e)*sin(e))/r+c*((4*r^2-y^2)^(1/2)* (r^2-d^2*(cos(e))^2)^(1/2)+y*d*cos(e)) ;

solve(f,y)
两个解：

ans =
-(-2*b^2*r+a^2*r+c^2*r……………………
-(-2*b^2*r+a^2*r+c^2*r+d^2*r+d*(……