Thread: Integral containing two separate sin functions

Hey all, my integration is a bit rusty so I'm having trouble with integrating a function thats something like:

sin(yx)sin(zx)dx

How would I go about a problem like that?

Originally Posted by blorpinbloo

Hey all, my integration is a bit rusty so I'm having trouble with integrating a function thats something like:

sin(yx)sin(zx)dx

How would I go about a problem like that?

Use the following trigonometric identity:

Originally Posted by blorpinbloo

Hey all, my integration is a bit rusty so I'm having trouble with integrating a function thats something like:

sin(yx)sin(zx)dx

How would I go about a problem like that?

It needs to be asked if and/or are functions of or if they are independent of ?

Assuming y and z are not functions of x, the integral is independent of these variables and y and z may be treated as constants. Then integration by parts (applied twice to get a multiple of the original integrand) makes short work of this integral.
Otherwise, you need to know those functions of x.