Cos(A-B) = cosAcosB + sinAsinB
<span>
cos(</span>π/2 - θ) = cos(π/2)cosθ + sin(π/2)sinθ
π/2 = 90°
cos(π/2) = cos90° = 0. sin(π/2) = sin90° = 1
cos(π/2 - θ) = cos(π/2)cosθ + sin(π/2)sin<span>θ
</span>
= 0*cosθ + 1*sin<span>θ = </span>sin<span>θ
Therefore </span>cos(π/2 - θ) = sin<span>θ
QED </span>
Answer:

Step-by-step explanation:
Hi there!

To get rid of the fraction
, multiply both sides of the equation by 3 (the denominator):

To get rid of the fraction
, multiply both sides of the equation by 5 (the denominator):

I hope this helps!
Answer:
C. 
Step-by-step explanation:
We want fg of x, so first we have to multiply f(x) times g(x).



We can cancel out an x from every term.

Let's rewind a little to get this into one of the answer choices.
is our answer.
Answer: Hello! The answer would be "8"
Step-by-step explanation:
When using the angle of 135 in each interior it would make a shape with 8 sides :)