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NCERT Class XI Mathematics - Trigonometric Functions - Solutions

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Question : 10 of 61
Marks: +1, -0
cot x = 34\frac{3}{4} , x lies in third quadrant.
Solution:  
cot x = 34\frac{3}{4} gives tan = 43\frac{4}{3}
csc2\csc^{2} x = 1 + cot2x\cot^{2} xcsc2\csc^{2} x = 1 + 916\frac{9}{16} = 2516\frac{25}{16}
⇒ cosec x = ± 54\frac{5}{4} ⇒ cosec x = - 54\frac{5}{4} [since x lies in third quadrant]
cosec x = 54-\frac{5}{4} gives sin x = 45-\frac{4}{5} , cos x = cot x × sin x
⇒ cos x = 34×(45)=35\frac{3}{4} \times \left(-\frac{4}{5}\right) = -\frac{3}{5} ⇒ sec x = 53-\frac{5}{3}
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