Question

sin 18° sin 42° sin 78° cosec 54°​

Answer 1

Sin18. Sin (60-18). Sin(60+18). Cosec54
=1/4 . Sin 3*18 . Cosec54
= 1/4 . Sin54. Cosec54
=1/4

Answer 2

Answer:

sin18 sin(60-18) sin(60+18) cosec54

$\frac{1}{4} sin \: 54 \times \frac{1}{sin54}$

since sinx*sin(60-x)*sin(60+x) = 1/4 sinx

and cosec x = 1/sinx

= 1/4

hope it helps you.....!

sorry for the Delay in answering

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