Question

Which is an equation of the cosine function that has a period of π5
?(1 point)
Responses

f(x)=cos(10x)

f left parenthesis x right parenthesis equals cosine left parenthesis 10 x right parenthesis

f(x)=cos(x5)

f left parenthesis x right parenthesis equals cosine left parenthesis Start Fraction x over 5 End Fraction right parenthesis

f(x)=cosx

f left parenthesis x right parenthesis equals cosine x

f(x)=cos(x10)

Answer 1

Period of cos(bx) is 2π/b. Set 2π/b = π/5 → b = 10. So f(x) = cos(10x).