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Can anyone solve this plz​

Answer»

To Find:

\Longrightarrow \sf \dfrac{sinA}{1 + cosA} + \dfrac{1 + cosA}{sinA}

Taking LCM we get:

\Longrightarrow \sf \dfrac{(sinA)(sinA) + (1 + cosA)(1 + cosA)}{(1 + cosA)(sinA)}

Using (a + B)(a + b) = (a + b)² we get:

\Longrightarrow \sf \dfrac{sin^2A + (1 + cosA)^2}{(1 + cosA)(sinA)}

Using (a + b)² = a² + b² + 2ab we get:

\Longrightarrow \sf \dfrac{sin^2A + (1)^{2}  + (cosA)^2 + 2(1)(cosA)}{(1 + cosA)(sinA)}

\Longrightarrow \sf \dfrac{sin^2A + 1 + cos^2A + 2cosA}{(1 + cosA)(sinA)}

\Longrightarrow \sf \dfrac{sin^2A + cos^2A + 1 + 2cosA}{(1 + cosA)(sinA)}

Using the identity sin²A + cos²A = 1 we get:

\Longrightarrow \sf \dfrac{1 + 1 + 2cosA}{(1 + cosA)(sinA)}

\Longrightarrow \sf \dfrac{2 + 2cosA}{(1 + cosA)(sinA)}

TAKE 2 out since it's common to both 2 and 2cosA.

\Longrightarrow \sf \dfrac{2(1 + cosA)}{(1 + cosA)(sinA)}

Cancelling (1 + cosA) in the numerator & DENOMINATOR we get:

\Longrightarrow \sf \dfrac{2}{sinA}

\Longrightarrow \sf 2 \times \dfrac{1}{sinA}

Using 1/sinA = cosecA

\Longrightarrow \sf 2cosecA

Hence solved.



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