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:
3x +2x-5+(-7x+8)=
-2x+3
Step-by-step explanation:
The answer for this question is D because you have 2 full squares and then one half of square so 2 1/2.
Answer:
The equation is 
at a rate of -23%.
Step-by-step explanation:
Decay can be represented by the equation 
. We can find the rate at which it decays by using t=3 hours and A=3000. This means 
in this context.
After substituting, we divided by 6000 to each side to get 0.5 on the left. Now to solve for r, we will take the natural log of both sides and use log rules to isolate r.
We know 
so we were able to cancel it out and divide both sides by 3.
We solve with a calculator 
We change -0.23 into a percent by multiplying by 100 to get -23% as the rate.
The equation is
