Question

Find values for θ that make each statement true (show steps)

1) sinθ = cos(25)
θ =


2) sin(θ/3 + 10 ) = cos θ
θ =

Answer 1

Explanation:

1. sinФ = cos 25

25 ° is in the between 0 and 90°

therefore it can simply represent

cosФ= sin (90-Ф) = sin (90 - 25) = sin 65

2. sin(Ф/3 + 10) = cos Ф

cos Ф = sin (90 -Ф)

sin(Ф/3 + 10) = cos Ф

sin(Ф/3 + 10) = cos Ф = sin(90-Ф)

Ф/3+10=90-Ф

10Ф+3/30 = 90-Ф

10Ф+3 = 30(90-Ф)

10Ф+3 = 2700-30Ф

10Ф+30Ф=2700-3

40Ф = 2697

Ф = 2697 / 40 = 67.425 ≅ 67.4°