First slide

Trigonometric Identities

Question

If $3 \tan A + 4 = 0$ then the value of 2 cot A -5 cos A + sin A is equal to

Moderate

A

$\frac{23}{10} if \frac{π}{2} < A < π$
B

$\frac{23}{10} if \frac{3 π}{2} < A < 2 π$
C

$\frac{- 53}{10} if \frac{π}{2} < A < π$
D

$\frac{- 53}{10} if \frac{3 π}{2} < A < 2 π$

Solution

We have $\tan A = - \frac{4}{3}$
lf A lies in 2nd quadrant, then
$\sin A = \frac{4}{5}, \cos A = \frac{- 3}{5}, and \cot A = \frac{- 3}{4}$
lf A lies in 4m quadrant, then
$\sin A = \frac{- 4}{5}, \cos A = \frac{3}{5} and \cot A = \frac{- 3}{4}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App