Question

怎么用matlab解常微分方程的初值问题？谁给个程序

Answer 1

Specifying the Independent Variable

dsolve('(Dy)^2 + y^2 = 1','s')

ans =
1
-1
cosh(C7 + s*i)
cosh(C11 - s*i)

Setting Initial and Boundary Conditions

dsolve('Dy = a*y', 'y(0) = b')

ans =
b*exp(a*t)

dsolve('D2y = -a^2*y', 'y(0) = 1', 'Dy(pi/a) = 0')

ans =
(1/exp(a*t*i))/2 + exp(a*t*i)/2

追问

这个式子，K,N都是常数，怎么在程序里定义挖，解不出底下上面那个解