Question

hey, I got the following problem.
Why is cos(2x)=cos(x+x) ? I don't why. Please help me :)

Answer 1

let's see x + x = 2x so... ahemm

Answer 2

2x=x+x

Answer 3

Oh my goodness, true, I did to much math today. thank you sou much guys!! :D

Answer 4

Because x + x = 2x. Remember that cos is a function operating on whatever the argument is. So if we have two things that are equal, when we plug them in to the function, we get the same output.

Answer 5

I got it, thanks!!!

Answer 6

Do math every day.