First slide

Monotonicity

Question

If the function $f (x) = \frac{Ksin x + 2 \cos x}{\sin x + \cos x}$ is strictly increasing for all values of x, then

Easy

A

K<1
B

K>1
C

K<2
D

K>2

Solution

Since $f (x) = \frac{Ksin x + 2 \cos x}{\sin x + \cos x}$ is strictly increasing for all x,
$f^{'} (x) > 0 for all x$
or $\frac{(K - 2) s e c^{2} x}{(\sin x + \cos x)^{2}} > 0 for all x$
or $K - 2 > 0 or K > 2$

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