If sin θ = (12)\Big(\dfrac{1}{2}\Big)(21), then the value of (15cot2θ+15)\Big(\dfrac{1}{5} \cot^2\theta + \dfrac{1}{5}\Big)(51cot2θ+51) is:
(15)\Big(\dfrac{1}{5}\Big)(51)
(45)\Big(\dfrac{4}{5}\Big)(54)
(1125)\Big(\dfrac{1}{125}\Big)(1251)
25
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Solving,
⇒(15cot2θ+15)⇒15(cot2θ+1)⇒15(cosec2θ).\Rightarrow \Big(\dfrac{1}{5} \cot^2\theta + \dfrac{1}{5}\Big) \\[1em] \Rightarrow \dfrac{1}{5} \Big(\cot^2\theta + 1 \Big) \\[1em] \Rightarrow \dfrac{1}{5} (\cosec^2 \theta).⇒(51cot2θ+51)⇒51(cot2θ+1)⇒51(cosec2θ).
We know that,
cosecθ=1sinθ⇒cosecθ=112=2⇒cosec2θ=22=4⇒15cosec2θ⇒15(4)⇒45.\cosec \theta = \dfrac{1}{\sin \theta } \\[1em] \Rightarrow \cosec \theta = \dfrac{1}{\dfrac{1}{2}} = 2\\[1em] \Rightarrow \cosec^2 \theta = 2^2 = 4 \\[1em] \Rightarrow \dfrac{1}{5}\cosec^2 \theta \\[1em] \Rightarrow \dfrac{1}{5}(4) \\[1em] \Rightarrow \dfrac{4}{5}.cosecθ=sinθ1⇒cosecθ=211=2⇒cosec2θ=22=4⇒51cosec2θ⇒51(4)⇒54.
Hence, option 2 is the correct option.
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In the adjoining figure, if PS = 14 cm, then the value of tan α is equal to:
(43)\Big(\dfrac{4}{3}\Big)(34)
(53)\Big(\dfrac{5}{3}\Big)(35)
(133)\Big(\dfrac{13}{3}\Big)(313)
(143)\Big(\dfrac{14}{3}\Big)(314)
The value of (1 + tan θ + sec θ)(1 + cot θ − cosec θ) is:
−4
−1
1
2
If cos θ = (23)\Big(\dfrac{2}{3}\Big)(32), then 2 sec2θ + 2 tan2θ − 7 is equal to:
0
3
4
If 24 cot θ = 7, then sin θ is equal to:
(247)\Big(\dfrac{24}{7}\Big)(724)
(2425)\Big(\dfrac{24}{25}\Big)(2524)
(725)\Big(\dfrac{7}{25}\Big)(257)
(2524)\Big(\dfrac{25}{24}\Big)(2425)