Question

Show that the function sinx+cosx is of period 2pi. Also prove that sinx+cosx=sqrt(2)sin(x+pi/4)

Answer 1

have no idea what to do with this one :-(

Answer 2

\[sinx+cosx=\sqrt2\sin(x+\frac{ \pi }{ 4 })\]

Answer 3

RHS: use
\[\sin(A+B)=\sin(A)\cos(B)+\cos(A)\sin(B)\]

Answer 4

what about that period Q

Answer 5

well, \[\cos\theta=\cos(\theta+2\pi)\]
so, start from let
\[\cos\theta=\cos(\theta+A)\]
solve for A

Answer 6

would that make sense?

Answer 7

sorry but I need to go somewhere i'll get back to u on this :)

Answer 8

I am back!!

Answer 9

sinx cos pi/4 + cosx sin pi/4 what's next?

Answer 10

@electrokid

Answer 11

help plz..... ??? where is everybody