Sine fuction

Question

If the amplitude, is sqrt(21) and the period is (10/3)pi, what is the sine function equation f(x)=   ?

Answer 1

f(x) = a sin (bθ), where a = amplitude, 2π/b = period

 

10π/3 = 2π/b

20π = 6π/b

b = 6π/20π

b = 0.3

 

f(x) = √21 sin (0.3θ)