Most Important Selected Qs for JEE AdvancedMathematicsApplication of Derivatives
f(x) is defined for x -1 and has a continuous derivate. If f satisfies f(0)=1, f^ (0)=0 ; (1+f(x)) f^ (x)=1+x . If x is positive then f^ (x) is
Options
- Aalways positive
- Balways negative
- Calways non-negative
- Dnone of these
Correct answer
A. always positive
Step-by-step solution
f^ (x)= 1+x 1+f(x) . Also f^ (x) 0 f^ (x) is increasing f^ (x) ^ (0)=0 x 0