Sin²5°+sin²10°+sin²15°+........sin²90° =? ?
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Answered by
71
Hey !!!!
Here is ur answer ....
from LHS
sin²5° +sin²10° + sin²15° +.........sin²90°
= (sin²5° + sin²85° )+(sin²10°+sin²80°) +....+(sin²40° +sin²50° )+sin²45° +sin²90°
= [sin²5° +sin²(90°-5°)] +[sin²10°+sin²(90°-10°)]+....+[sin²40° +sin²(90°-40°)] +sin245° +sin²90°
= (sin²5° +cos²5° ) +(sin²10°+cos²10°)+....+(sin²40° +cos²40°)+sin²45°+sin²90°
=1+1+1+1+1+1+1+1+(1/√2)²+1
=9+1/2
=] 9+1/2 =19/2 Answer ...
hope it helps !!
#Rajukumar111
Here is ur answer ....
from LHS
sin²5° +sin²10° + sin²15° +.........sin²90°
= (sin²5° + sin²85° )+(sin²10°+sin²80°) +....+(sin²40° +sin²50° )+sin²45° +sin²90°
= [sin²5° +sin²(90°-5°)] +[sin²10°+sin²(90°-10°)]+....+[sin²40° +sin²(90°-40°)] +sin245° +sin²90°
= (sin²5° +cos²5° ) +(sin²10°+cos²10°)+....+(sin²40° +cos²40°)+sin²45°+sin²90°
=1+1+1+1+1+1+1+1+(1/√2)²+1
=9+1/2
=] 9+1/2 =19/2 Answer ...
hope it helps !!
#Rajukumar111
Aartiraju:
thanks Rajukumar11
wrong
there will be 8 on the place of 9
5,10,15,20,25,30,35,40 will make pair so these are 8 only
Answered by
5
Then answer is
19/2
Follow me if it helps
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