Question

Select the expression that is equivalent to cos (5pi/13)

a. -sin(3pi/26)
b. sin(3pi/26)
c. cos(3pi/26)
d. -cos(3pi/26)

Answer 1

The expression that is equivalent to cos(5π/13) is -cos(3π/26)

Therefore, the answer is option d.) -cos(3pi/26)

Step-by-step explanation:

To find the equivalent expression, we can use the identity cos(θ) = cos(-θ).

Since 5π/13 is in the third quadrant, its equivalent angle in the first quadrant is 3π/26.

The expression that is equivalent to cos(5π/13) is -cos(3π/26).