Question

1)
cos 1° + cos 2° + cos 3° +...+cos 179°=​

Answer 1

Answer:

given expression can be rearranged as

(Cos 1 +cos 179) +(cos 2+ cos 178) + (cos 3+cos 177)+.......................(cos89+ cos91) +cos 90 +cos 180

Step-by-step explanation:

but we know that cos( 180 - X) equal to - cos x , where is X is angle in degrees so all the bracket total except last 2 term will be zero

so given expression is zero + cos 90 + cos 180

= 0 + 0 + (-1)

= -1

Answer 2

answer is 0

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