SSC CPO SI and ASI Model Paper 10

Question : 104 of 200

Marks: +1, -0

If 0°< (2b + 30°) < 90°and sin(2a – 30°) = cos(2b + 30°) then find cot(a + b). a and b are acute angles.

Solution:

(3) sin(2a – 30°) = cos(2b + 30°)
As a and b are acute angles, therefore,cos(2b + 30°) = sin(90°– 2b– 30°)
∴sin(2a°-30°) = sin(60°-2b)

⇒2a + 2b = 90°

⇒a + b = 45°

∴cot(a + b) = cot45°= 1

Go to Question:

Prev Question

Next Question