if sin theta= 0.4, what is the exact value of sin theta+ cos(pi/2-theta)

Question

if sin theta= 0.4, what is the exact value of sin theta+ cos(pi/2-theta)

Answer 1

Recall that

 

cos(π/2 - θ) = sinθ,

 

so

 

sinθ + cos(π/2 - θ) = sinθ + sinθ = 2sinθ

 

Plug in

 

sinθ = 0.4 

 

and get your answer.