Question

answer this question which is attached with this image pls​

Answer 1

We have to prove:

sin20/cos70 + tan51/cot39 - 2sec10. sin80 =0

LHS =

sin(90 - 20)/cos70 + tan(90 - 51)/cot39

- 2 * 1/cos10 * sin(90 - 80)

cos70/cos70 + cot39/cot39 - 2 * 1/cos10 * cos10

1 + 1 - 2

2 - 2

= 0

= RHS

Hence, Proved