$\"\"$

\

Fourier sine series coefficient is $\"\"$ .

\

Let $\"\"$ , where $\"\"$ and $\"\"$

\

Find $\"\"$ .

\

Consider $\"\"$ .

\

Find the integral using integration by parts.

\

Formula for integration by parts: $\"\"$ .

\

Here $\"\"$ and $\"\"$ .

\

Consider $\"\"$ .

\

Apply derivative on each side.

\

$\"\"$ .

\

Now $\"\"$ .

\

Apply integral on each side.

\

$\"\"$

\

Substitute corresponding values in integration by parts formula.

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Consider $\"\"$ .

\

Find the integral using integration by parts.

\

Formula for integration by parts: $\"\"$ .

\

Here $\"\"$ and $\"\"$ .

\

Consider $\"\"$ .

\

Apply derivative on each side.

\

$\"\"$ .

\

Consider $\"\"$ .

\

Apply integral on each side.

\

$\"\"$

\

Substitute corresponding values in integration by parts formula.

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$ \ \

\

$\"\"$ .

\

Substitute the results of (1) and (2) in $\"\"$ .

\

$\"\"$

\

$\"\"$ .

\

$\"\"$

\

$\"\"$ .