Symbolic substraction of multiple valued functions

Question

Meva 2016-10-21

0
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https://ww2.mathworks.cn/matlabcentral/answers/308457-symbolic-substraction-of-multiple-valued-functions

评论： Meva 2016-10-22

Hello,

I have two equations which are the same but in a different format. byhand is arranged version of thetadouble function. If I substract byhand from thetadouble I should get zero, but instead Matlab just repeats what I typed. Please see below.

syms thetadouble(h, theta, kappa, b, a, c, gamma) byhand(h, theta, kappa, b, a, c, gamma)
thetadouble = (sqrt(a*kappa)*(a^3 *(1 - 2 *b) ...
    - a^2 *(-1 + 2 * b) *(1 - 2*c + 2 * c^2) *kappa - (b - c) *(-1 + c) ...
    *c *(h + theta - b *theta)^2 *kappa + ...
a *((-1 + b + c) * h^2 -2 *(-1 + b) *(-1 + b + c) *h*theta ...
+ (-1 + b)^2 *(-1 + b + c) * theta^2 - (-1 + 2*b) *(-1 + c)^2 *c^2 *kappa^2)) ...
- (b - c) *(h + theta - b *theta)^2 *...
(a^2 + a *(1 - 2 *c + 2 *c^2) *kappa + (-1 + c)^2 *c^2 *kappa^2) ...
*atan((-1 + c)*kappa/a) + (b -c) * (h + theta - b *theta)^2*(a^2 + a *(1 - 2 *c + 2 *c^2) * kappa + (-1 + c)^2 *c^2*kappa^2) ...
    *atan(c *kappa/a))...
    /(4*a^(3/2)*gamma *sqrt(kappa)...
    *(a +(-1 + c)^2*kappa)* (a +c^2 *kappa));
byhand = (sqrt(a*kappa)*(a*(1 - 2*b)*(a^2 + kappa*a*(1 - 2 *c + 2 *c^2) + ...
         c^2*kappa^2 *(1 - c)^2) + (b - c)*(1 - c)*c*(h + (1 - b)*theta)^2*kappa ...
         + a*(b - 1 + c)*(h + (1 - b)*theta)^2)...
         + (b - c) *(h + (1 - b )* theta)^2 * ...
         (a^2 + a *(1 - 2 *c + 2 *c^2) ...
         * kappa + (-1 + c)^2 *c^2*kappa^2)*(atan((1 - c) * sqrt(kappa/a))+ ...
      atan(c * sqrt(kappa/a))))/((4 *a^(3/2) *gamma *sqrt(kappa) ...
          *(a + (-1 + c)^2 *kappa)*(a +c^2 *kappa)));
diff = thetadouble - byhand