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Question
Evaluate: `sin 50^@/cos 40^@ + (cosec 40^@)/sec 50^@ - 4 cos 50^@ cosec 40^@`
Solution
Sin 50° = sin (90° - 40°) = cos 40°
Cosec 40° = cosec (90° - 50°) = sec 50°
Cos 50° = cos (90° - 40°) = sin 40°
`=> cos 40^@/cos 40^@ + (sec 50^@)/(sec 50^@) - 4 sin 40^@ cosec 40^@`
1 + 1 – 4 = − 2 [∵ Sin 40° cosec 40° = 1]
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