# Math Help - graphing of sin and cos

1. ## graphing of sin and cos

Hello guys can you help me identify the parts of the this functions

A) -5 sin x/2

What I know about this function is the amplitude which is 5 and it is reflected to the x axis. But I dont know what does the x/2 mean in the function.

B) -3 cos 2pi x

thanks in advanced

2. The x/2 just increases the period. The normal period is [0,2pi], but the x/2 makes it [0, 4pi]. 2x would make it [0,pi] etc.

3. That makes sense. Thank you very much for your help.

Godbless

4. A way of seeing that in general is to think "the period of sin(t) is $2\pi$ so the period of sin(a) is given by $a= 2\pi$" where a is any expression. Here a= x/2 so $x/2= 2\pi$ gives $x= 4\pi$ as the period.

5. so since the period of sin is 2pi its was divided x/2 in order to get 4pi? is this correct?