Cos 5+Cos 10+Cos 15+Cos 20+Cos 25 upto Cos 180
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Answered by
1
Answer:
The correct question is To find the value of cos²5 + cos²10 + ... + cos²85 + cos²90.
ANSWER:
The value of cos²5+cos²10+ ...+cos²85+cos²90 is 17/2.
We know that sin(90-θ) = cosθ.
We have to find the value of cos²5+cos²10+cos²15+cos²20+...+cos²90
Total number of terms = 18
Now, we substitute cosθ = sin(90-θ).
cos²5 + cos²10 + cos²15 + .. + cos²40 + cos²45 + sin²(90-50) + sin²(90-55) +...
+ sin²(90-80)+hi sin²(90-85)+ cos²90
= (cos²5+s
in²5) + (cos²10+sin²10) + (cos²15+sin²15)+ .. (cos²40+sin²40) + cos²45+cos²90
= 8+1/2+0= 17/2
Answered by
0
Answer:
17 /2
HOPE IT HELPS U
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