Question

If θ is a first-quadrant angle in standard position with P(u, v) = (3, 4), evaluate cos 2 θ . -7/25 -1/5 7/25

Answer 1

Answer:

-7/25.

Step-by-step explanation:

From the given point P we see that the hypotenuse =  √(3*2 + 4^2) = 5.

So cos  θ = 3/5

cos 2 θ =  2 cos^2 θ - 1

= 2 * (3/5)^2 -1

= -7/25.