$\"\"$

Multiply the numerator and denominator by $\"\"$ .

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According to Pythagorean trigonometry identity $\"\"$ .

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Split into separate integrals.

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According to Pythagorean trigonometry identity $\"\"$

$\"\"$

Again Split into separate integrals.

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Let u = cosx then du = - sinx dx

$\"\"$

Therefore, u = cos x

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