Practicing Success
If $5 \sin ^2 \theta+14 \cos \theta=13,0^{\circ}<\theta<90^{\circ}$, then what is the value of $\frac{\sec \theta+\cot \theta}{{cosec} \theta+\tan \theta}$ ? |
$\frac{32}{27}$ $\frac{21}{28}$ $\frac{31}{29}$ $\frac{9}{8}$ |
$\frac{31}{29}$ |
5 sin²θ + 14 cosθ = 13 { using , sin²θ + cos²θ = 1 } 5 ( 1 - cos²θ ) + 14 cosθ = 13 5 cos²θ - 14 cosθ + 8 = 0 5 cos²θ - 10 cosθ - 4 cosθ + 8 = 0 5 cosθ (cosθ - 2) - 4 ( cosθ - 2 ) = 0 (5 cosθ - 4) . ( cosθ - 2 ) = 0 EIther (5 cosθ - 4) = 0 Or ( cosθ - 2 ) = 0 ( cosθ - 2 ) = 0 is not possible. So, 5 cosθ - 4 = 0 cosθ = \(\frac{4}{5}\) { cosθ = \(\frac{B}{H}\) } By using pythagoras theorem, P² + B² = H² P² + 4² = 5² P = 3 Now, \(\frac{secθ +cotθ}{cosecθ + tanθ}\) = \(\frac{B/H +B/P}{H/P + P/B}\) = \(\frac{4/5 +4/3}{5/3 + 3/4}\) = \(\frac{31/12}{ 29/12 }\) = \(\frac{31}{ 29 }\)
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