Am I allowed to open these brackets of t the angle?

Sin(X)Cos(90-V)
can it equal to sin(x)
(Cos(90)-cos(v))?????????????

1 Answer
Nov 28, 2017

Please see below.

Explanation:

.

I think you want to know if:

cos(90-v)=cos90-cosv

The answer is no. There is a formula for this:

cos(a-b)=cosacosb+sinasinb

Therefore:

cos(90-v)=cos90cosv+sin90sinv

cos(90-v)=(0)(cosv)+(1)(sinv)=0+sinv

cos(90-v)=sinv