Trigonometric Identities Question 132

Question: If $ \tan \theta =\frac{-4}{3}, $ then $ \sin \theta = $

[IIT 1979; Pb. CET 1995; Orissa JEE 2002]

Options:

A) - 4/5 but not 4/5

B) - 4/5 or 4/5

C) 4/5 but not - 4/5

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

Since $ cose{c^{2}}\theta =1+{{\cot }^{2}}\theta =1+\frac{9}{16}=\frac{25}{16} $ $ ( \because \tan \theta =-\frac{4}{3} ) $ $ {{\sin }^{2}}\theta =\frac{1}{cose{c^{2}}\theta }=\frac{16}{25}\Rightarrow \sin \theta =\pm \frac{4}{5}, $ Both the values are acceptable, since $ \tan \theta =-\frac{4}{3} $ $ ,i.e.,\theta $ lies in $ 2^{nd} $ or $ 4^{th} $ quadrant.