Question

Calc AB multiple choice. Please help

Answer 1

B is the right answer.

Answer 2

You start off with 4*(cos(x+(pi/3)))

Let's place the 4 aside for the time being:

Cos(u+j) = cos(u)*cos(j) - sin(u)*sin(j)

cos(x+(pi/3)) = cos(x)*cos(pi/3) - sin(x)*sin(pi/3)

cos(x+(pi/3)) = cos(x)/2 - (sqrt(3)/2)*sin(x)

Multiplying by the 4 we put aside:

4*cos(x+(pi/3)) = 2*cos(x) - 2*sqrt(3)*sin(x)

The correct answer is B