Question

A function has the equation Acos3t + Bsin3t. Find the value of time period.

(a) π/3

(b) 2π/3

(c) Aπ/3 + Bπ/3

(d) π/3A + π/3B

Answer 1

Correct answer is (b) 2π/3

The best I can explain: Acos3t + Bsin3t = √(A^2 + B^2) [sin(3t+a)],

where sin(a) = (A/√(A^2 + B^2)).

Thus, the time period will be 2π/3.

Here, √(A^2 + B^2) will be the amplitude.