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    The value of (sec∅ − tan∅)² (1 + sin∅)² ÷ cos²∅ is
    Question

    The value of (sec∅ − tan∅)² (1 + sin∅)² ÷ cos²∅ is

    A.

    −2

    B.

    2

    C.

    0

    D.

    1

    Correct option is D

    Given:

     (sec∅ − tan∅)² (1 + sin∅)² ÷ cos²∅ 

     =(1cossincos)2×(1+sin)21sin2 =(1sincos)2×(1+sin)(1sin) =(1sin)2cos2×(1+sin)(1sin) =(1sin)2(1sin)(1+sin)×(1+sin)(1sin) =1= (\frac{1}{cos∅} − \frac{sin∅}{cos∅})² \times \frac{(1 + sin∅)² }{1 - sin^2∅}\\\ \\= (\frac{1 -sin∅}{cos∅})^2 \times \frac{(1 + sin∅)}{(1 - sin∅)}\\\ \\= \frac{(1 -sin∅)^2}{cos^2∅} \times \frac{(1 + sin∅)}{(1 - sin∅)}\\\ \\= \frac{(1 -sin∅)^2}{(1 -sin∅)(1 +sin∅)} \times \frac{(1 + sin∅)}{(1 - sin∅)}\\\ \\= 1 

    Identity Used: 

    sin2θ+cos2θ=1sin^2\theta + cos^2 \theta = 1

    Solution: 

     (sec∅ − tan∅)² (1 + sin∅)² ÷ cos²∅ 

    =(1cossincos)2×(1+sin)21sin2 =(1sincos)2×(1+sin)(1sin) =(1sin)2cos2×(1+sin)(1sin) =(1sin)2(1sin)(1+sin)×(1+sin)(1sin) =1= (\frac{1}{cos∅} − \frac{sin∅}{cos∅})² \times \frac{(1 + sin∅)² }{1 - sin^2∅}\\\ \\= (\frac{1 -sin∅}{cos∅})^2 \times \frac{(1 + sin∅)}{(1 - sin∅)}\\\ \\= \frac{(1 -sin∅)^2}{cos^2∅} \times \frac{(1 + sin∅)}{(1 - sin∅)}\\\ \\= \frac{(1 -sin∅)^2}{(1 -sin∅)(1 +sin∅)} \times \frac{(1 + sin∅)}{(1 - sin∅)}\\\ \\= 1

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