JEE Main20258 Apr 2025Evening ShiftMathematicsApplication of DerivativesActual
Let the function f(x)= x 3 + 3 x +3, x 0 be strictly increasing in (- , ₁ ) U ( ₂, ) and strictly decreasing in ( ₃, ₄ ) U ( ₄, ₅ ) . Then _ i =1 ^5 _ i ^2 is equal to :-
Options
- A48
- B28
- C40
- D36
Correct answer
D. 36
Step-by-step solution
aligned & f(x)= x 3 + 3 x +3, x 0 & f^ (x)= 1 3 - 3 x^2 =0 x= 3 & f^ (x)= x^2-3 3 x^2 aligned aligned & f ^ ( x ) 0 (- ,-3) (3, ) increasing & f ^ ( x ) 0 (-3,0) (0,3) decreasing aligned _ i=1 ^5 _i^2=(-3)^2+(3)^2+(-3)^2+(0)^2+(3)^2 =36