Question

11. The value of cos 0° + cos 1° + ........ + cos 180º =
find the sum​

Answer 1

Answer:

sum is 0.......................

Answer 2

Answer:

-1

Step-by-step explanation:

cos 0° + cos 1° + ........ + cos 180º

(Cos 1 + cos 179) + (cos2 + cos 178) + (cos3+ cos177) +…. + (cos89 + cos 91) + (cos90) + cos180

But we know that: cos(180 - x)= - cos x, where x is angle in degree. So all the bracket totals except last 2 terms will be zero.

So given expression is: 0 + (cos90) + ( cos180)

= 0 + 0 + (-1)

=-1.