请大家帮我看看这几道高等数学题怎么做。要有详细过程。好的我会采纳的。
另外如果我有看不懂的地方追问的时候,大神要耐心的给我指导。这样我才会采纳。
谢谢各位! 展开
∫e^(cos2x)sin2xdx = (-1/2)∫e^(cos2x)dcos2x = -e^(cos2x)/2+C.
∫dx/√(2+2x+x^2)=∫d(x+1)/√[1+(x+1)^2)] 令 x+1=tanu
=∫(secu)^2du/secu =∫secudu = ln |secu+tanu|+C
= ln |√(2+2x+x^2)+x+1|+C
令 x=asecu,则 I =∫√(x^2-a^2)dx/x =∫a^2(tanu)^2secudu/asecu
=∫a(tanu)^2du
= a∫[(secu)^2-1]du=a(tanu-u)+C=√(x^2-a^2)-a[arccos(a/x)]+C
令 x=tanu, 则 I =∫dx/[x^2√(x^2+1)]=∫secudu/(tanu)^2
=∫cosudu/(sinu)^2 =∫dsinu/(sinu)^2=-1/sinu+C=-√(x^2+1)/x+C.
∫dx/(1+e^x)=∫(1+e^x-e^x)dx/[(1+e^x)=∫[1-e^x/[(1+e^x)]dx
=∫dx-∫e^xdx/(1+e^x)=x-∫d(e^x+1)/(1+e^x)=x-ln(1+e^x)+C
∫dx/(xlnx*lnlnx)=
∫dlnx/(lnx*lnlnx)=∫dlnlnx/(lnlnx)=lnlnlnx+C
∫(secx)^4dx=∫(secx)^2dtanx=∫[(tanx)^2+1]dtanx=(tanx)^3/3+tanx+C
???好像还没做完呢。。
8.. 令 x=sinu,则 I= ∫ dx/[(1+x^2)√(1-x^2)]=∫ du/[1+(sinu)^2]
=∫ du/[2-(cosu)^2] =(√2/4)∫ [1/(√2+cosu)+1/(√2-cosu)]du
=(√2/4){2arctan[tan(u/2)/(√2+1)]+2arctan[tan(u/2)/(√2-1)]}+C
=(√2/2){arctan[(√2-1)tan(u/2)]+arctan[(√2+1)tan(u/2)]}+C
=(√2/2){arctan[(√2-1)tan(arcsinx/2)]+arctan[(√2+1)tan(arcsinx/2)]}+C
9 ∫ x^(1/2)dx/[x^(1/2)-x^(1/4)] =∫ x^(1/4)dx/[x^(1/4)-1] 令 x^(1/4)=u
= ∫ u*4u^3du/(u-1)= 4∫ [u^3+u^2+u+1+1/(u-1)]du
= u^4+(4/3)u^3+2u^2+4u+4ln(u-1)+C
=x+(4/3)x^(3/4)+2x^(1/2)+4x^(1/4)+4ln[x^(1/4)-1]+C
题太多了!