如何从现有功能中组装新功能？

Question

我有一个函数kappa，它包含另外两个函数sigma_和sigma__。 我得到的错误是

error: binary operator '.^' not implemented for 'function handle' by 'scalar' operations
error: called from
at line -1 column -1

我的代码是

>> syms epsilon
>> a =  0.36990
>> b =  2.6474
>> sigma = @(epsilon) 10 .^ (a * log (epsilon) + b)
>> sigma_=@(epsilon) diff(sigma)
>> sigma__=@(epsilon) diff(sigma_)
>> kappa=@(epsilon) (sigma__)/(1+sigma_.^2).^(3/2)

>> kappa(1)
error: binary operator '.^' not implemented for 'function handle' by'scalar' operations
error: called from
at line -1 column -1

我编辑了我的代码：

>> sigma_ = @(epsilon) diff (sigma (epsilon))
>> sigma__=@(epsilon) diff(sigma_(epsilon))
>> sigma_(1)
ans = [](0x0)
>> kappa=@(epsilon) (sigma__(epsilon))/(1+sigma_(epsilon).^2).^(3/2)
>> kappa(1)
ans = [](0x0)