# Integration matlab

1. Oct 15, 2009

### sara_87

1. The problem statement, all variables and given/known data

If i want to evaluate the following integral:
$$\int(sinx)^{y-3} dx$$

using Matlab.

2. Relevant equations

3. The attempt at a solution

i first defined the variables x and y:
syms x
syms y
then i typed the integral;
int(sin(x)^(3-y),x)
but it doesnt give me the integral, it says:
Warning: Explicit integral could not be found.
why?

2. Oct 15, 2009

### MATLABdude

You may want to refer to this thread:

EDIT: Also, are you sure that y (as a variable, and not as a constant defined elsewhere) is supposed to be in your equation? You'll need to solve a differential equation, if that is the case.

3. Oct 15, 2009

### sara_87

y is a constant but we are not given the value so the answer should be in terms of y.
i want to integrate:
$$\frac{(cosy)^{2b-3}}{(siny)^{b-1}}$$
but i dont know how to i tried integration by parts repeatedly but it didnt work
so im trying to use Matlab.
I did:
syms x
syms y
syms b
int((cos(y))^(2b-3)/((sin(y))^(b-1)),x)
but it didnt work.
do you have any ideas how to find this integral analytically or using Matlab?