Algebra 3

For x ε (0, π/2) and sin x = 1/3,

if \sum_{n=0}^{\infty }\frac{sin(nx)}{3^{n}}=\frac{a+b\sqrt{b}}{c}

then find the value of (a + b + c), where a, b, c are positive integers.

3 Answers

591
Akshay Ginodia ·

41?

2305
Shaswata Roy ·

Σsin(nx)3n = imaginary part of Σeinx3n = 11-eix3

Here, eix = 2√23+i3

On simplifying the RHS we get,

Σsin(nx)3n = 5+2√234

a+b+c = 41

1357
Manish Shankar ·

Yes it is

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