Question

6. °,
If cos (40° + x) = sin 30°, find the value of
[CBSE 2015]
(2)
X.​

Answer 1

Answer:

cos (90-30)=sin 30

therefore cos 60=cos (40° + x)

40+x=60

x=60-40=20

Answer 2

Answer:

x = 20°

Step-by-step explanation:

cos (40° + x) = sin 30°

We know that,

sin θ = cos (90° - θ)

So,

sin 30° = cos(90° - 30°)

∴ sin 30° = cos 60°

→ cos (40° + x) = cos 60°

→ 40° + x = 60°

→ x = 60° - 40°

→ x = 20°