Hello fellow mathematicians,

I've missed few classes and I ran into a big problem while doing a homework.

My question is going to be very straightforward, and I hopefully will get an answer from you soon.

Here are the two simple tasks which I'm doing

http://img140.imageshack.us/my.php?i...uestionhi0.jpg

My question is, how can I simplify these tasks.

As for 1341 excercise I want to know a way how to simplify cos 4x and sin 4x.

And as for 1349 excercise, I would like to know the answer whether there is a way to simplify sin^2x and sin^x.

I know this may sound funny, but I've forgotten how to do that and was trying all day long to figure out what I'm missing . Thanks for a help in advance.