1)

If f:R→ R  is differentiable function such that f'(x) >2f(x) for all x ε R, and f(0)=1 then


A) $f(x)\gt e^{2x}in (0,\infty)$

B) $f(x)\lt;e^{2x}in (0,\alpha)$

C) f(x) is increasing in $(0,\infty)$

D) f(x) decresing in $(0,\infty)$

Answer:

Option A,C

Explanation:

f'(x) >2f(x)

$\Rightarrow$   $\frac{dy}{y}>2dx$

$\Rightarrow$   $\int_{1}^{f(x)} \frac{dy}{y}>2\int_{0}^{x} dx$

 $ln(f(x))>2x$

 $\therefore$  f(x) >e2x

Also as f'(x)>2f(x)

 $\therefore$  f'(x)>2c2x>0