Question

Last question.

"Show (by expanding) that sqrt(2) * sin[x + (pi / 4)] = sinx + cosx."

Answer 1

I'm not really sure where to start. But I've expanded

\[\sin (x + \frac{ \pi }{ 4 })\]
using the two-angle formula.

Answer 2

yes that's right, just continue it..
do you know what's the value of sin(pi/4) and cos(pi/4) ?

Answer 3

\[\frac{ 1 }{ \sqrt{2} }\]

Answer 4

correct! then simplify ....

Answer 5

Oh, I understand now! I see how the sqrt(2) cancels with those now.

Answer 6

Thank you for that! I'll give it another go.

Answer 7

you're welcome