How to integrate the function with 'arctan'

Hi, all! I try to interated the following fuction:

clc clear all syms x y z I1=int(2*x^2+3*y^3+4*z^4,x,0,arctan(y/z)) I2=int(I1,y,1,2) I3=int(I2,z,1,3)

But the error turns out to be: Undefined function 'arctan' for input arguments of type 'sym'.

How to solve this promblem, since x is dependent on y and z. Thanks

Answer 1

[John D'Errico]

It might be because arctan IS an undefined function. You can't call some function anything you wish and expect MATLAB to know what you mean, even if that is what you tend to call it in real life or in some other programming language.

atan however, IS defined, and does what I presume you need. In some cases, atan2, the two argument (4 quadrant) version of the inverse tangent is to be preferred.

[hapseeker]

THANKS John. It's really helpful.