cos10°cos50°cos70°=√3/8
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Answer:
The answer for this question is
= ( cos 10 cos 50 )cos 70
= 1/2 (2cos10cos50) cos 70
= 1/2 (cos 60+cos 40) cos 70
WKT value of cos 60 is 1/2 . put the value in next step
=1/2 (1/2 + cos 40) cos 70
= 1/2 ( cos 70/2 +cos 70 cos 40)
= 1/2 ( cos 70+cos 70 cos 40/2)
= 1/4 (cos 70 + 2 cos 70 cos 40)
= 1/4 (cos 70 + cos 110+ cos 30)
= 1/4 ( cos 70+ cos 180-70 + cos 30)
= 1/4 (cos 70- cos 70 + cos 30)
= 1/4 * √3/2
= √3/8
hence proved
Step-by-step explanation:
Hope this answer help u!!!!! byee
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