AP EAMCET201822 Apr 2018Evening ShiftMathematicsApplication of DerivativesActual
If x>0 , then x 1+x - (1+x)
Options
- Ais less than zero
- Bis greater than zero
- Cis equal to zero
- Dtakes all the real values
Correct answer
A. is less than zero
Step-by-step solution
Let a function f(x)= x 1+x - (1+x) , for x>0 aligned f^ (x) & = (x+1)-x (1+x)^2 - 1 (1+x) & = 1 (1+x)^2 - 1 1+x = 1-(1+x) (1+x)^2 & = -x (1+x)^2 0 aligned f^ (x) 0 f(x) is a strictly decreasing function for x < 0 . Now, f (0⁺ )=0 So, f(x) < 0