If sin(5x – 40°) = cos (5y + 40°), then the value of x + y is:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 18°.
sin(5x - 40°) = cos(5y + 40°)
If sin(A) = cos(B), then A + B = 90°
So, (5x - 40°) + (5y + 40°) = 90°
⇒ 5x + 5y = 90°
⇒ x + y = 18°