Click to Chat
1800-1023-196
+91-120-4616500
CART 0
Use Coupon: CART20 and get 20% off on all online Study Material
Welcome User
OR
LOGIN
Complete Your Registration (Step 2 of 2 )
Cos1+cos2+cos3+...cos180=?Please give me the answer
Dear student As cos 179 = cos (180-1) = - cos1SimilarlyCos 178 = - cos2Cos 177 = - cos3 Hencw when adding all terms cancelled out.Only cos90 + cos180 is remaining Now cos 90 = 0 and cos 180 = - 1 Hence final answer is -1.
Dear student The given expression can be rearranged as:(Cos 1 + cos 179) + (cos2 + cos 178) + (cos3+ cos177) +…. + (cos89 + cos 91) + (cos90) + cos180But 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.Answer: -1.
Post Question
Dear , Preparing for entrance exams? Register yourself for the free demo class from askiitians.
points won -