Question

Prove that: sin 50 +cos 80=√3 cos 70​

Answer 1

Answer:

L.H.S. :- sin 40 - cos 70 using sin C - sin D 2cos

2

C+D

sin

2

C−D

⇒sin40−cos(90−20)

⇒sin40−sin20

⇒2cos30.sin10. sin(90−80)=cos80

⇒2

2

3

×cos80

=

3

cos80

∘

R.H.S