Most Important Selected Qs for JEE AdvancedMathematicsApplication of Derivatives
Paragraph: Let f: R R, y=f(x), f(0)=0, (x) 0 and f^ (x) 0 . Three points A( , f( )), B( , f( )), C(y, f(y)) on y=f(x) such that 0 Question: Which of the following is false
Options
- Af( ) (f( ))
- Bf( ) f( )
- Cf( ) (f( ))
- D(f( )) f( )
Correct answer
B. f( ) f( )
Step-by-step solution
Consider g ( x )= f ( x ) x g^ (x)= f^ (x) x-f(x) x^2 = f^ (x) x^2 (x- f(x) f^ (x) ) as f^ (x) x^2 0 Let h(x)=x- f(x) f^ (x) h^ (x)=1- f^ (x)^2-f(x) f^ (x) f^ (x)^2 = f(x) f^ (x) f^ (x)^2 0 x- f(x) f^ (x) is increasing function aligned & x- f(x) f^ (x) 0- f(0) f^ (0) =0 & g^ (x) 0 & f(y) y f( ) f( ) aligned Satisfies A, C. D