Question

verify that cos (90 degrees +x)=-sin x

Answer 1

I suggest to try some angles. 90 degrees, 30 degrees, 180 degrees, 60 degrees, etc.
Do you know the trig functions of those special angles?

Answer 2

i know some of them but i dont know which one to use haha

Answer 3

wait wait i think i do

Answer 4

cos (a-b)=cos a cos b+ sin a sin b

Answer 5

No, like do you know cos(60) = sin(30) = 1/2?

Answer 6

whot.

Answer 7

Ugh, let's just use angles 90, 180, and 270 degrees. You know the trig functions of those, right?

Answer 8

no ha im very confused deary