Practicing Success
If the function $f(x)=2 \tan x+(2 a+1) \log _e|\sec x|+(a-2) x$ is increasing on R, then |
$a \in(1 / 2, \infty)$ $a \in(-1 / 2,1 / 2)$ $a=1 / 2$ $a \in R$ |
$a=1 / 2$ |
If $f(x)=2 \tan x+(2 a+1) \log _e|\sec x|+(a-2) x$ is increasing on R, then $f'(x) \geq 0$ for all $x \in R$ $\Rightarrow 2 \sec ^2 x+(2 a+1) \tan x+(a-2) \geq 0$ for all $x \in R$ $\Rightarrow 2 \tan ^2 x+(2 a+1) \tan x+a \geq 0$ for all $x \in R$ $\Rightarrow (2 a+1)^2-8 a \leq 0 \Rightarrow(2 a-1)^2 \leq 0 \Rightarrow a=\frac{1}{2}$ |