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Question
Prove that `sin 70^@/cos 20^@ + (cosec 20^@)/sec 70^@ - 2 cos 20^@ cosec 20^@ = 0`
Solution
Sin (70°) = sin (90° - 20°) = cos 20°
Cos 70° = cos (90° - 20°) = sin 20°
`=> cos 20^@/cos 20^@ + sec 70^@/sec 70^@ - 2 sin 20 cosec 20^@`
1 + 1 - 2(1) = 0
∴ LHS = RHS Hence proved
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