MHT CET202411 May 2024Morning ShiftMathematicsApplication of DerivativesActual
If f (x)=x^3-6 x^2+9 x+3 is monotonically decreasing function, then x lies in
Options
- A(3, )
- B(1,3)
- C[3, )
- D[0,3]
Correct answer
B. (1,3)
Step-by-step solution
array ll & f (x)=x^3-6 x^2+9 x+3 & f ^ (x)=3 x^2-12 x+9 array Since f (x) is monotonically decreasing, aligned & f ^ (x) 0 & 3 x^2-12 x+9 0 & x^2-4 x+3 0 & (x-3)(x-1) 0 & x (1,3) aligned