Calculate the sum:
S = cosϕ + acos 2ϕ + a ^ 2 cos 3ϕ +… + a ^ (n-1) cos nϕ
I think this question is related to Euler's number? Like, if I substitute cosϕ as e^iϕ , then it will be a series which will have cosϕ + acos 2ϕ + a ^ 2 cos 3ϕ +… + a ^ (n-1) cos nϕ as it's real part. Is the logic correct?
I need step wise solution to this since I'm stuck.
S = cosϕ + acos 2ϕ + a ^ 2 cos 3ϕ +… + a ^ (n-1) cos nϕ
I think this question is related to Euler's number? Like, if I substitute cosϕ as e^iϕ , then it will be a series which will have cosϕ + acos 2ϕ + a ^ 2 cos 3ϕ +… + a ^ (n-1) cos nϕ as it's real part. Is the logic correct?
I need step wise solution to this since I'm stuck.