AP EAMCET2009MathematicsApplication of Derivatives
The function f(x)=x^3+a x^2+b x+c, a^2 3 b has
Options
- Aone maximum value
- Bno extreme value
- Cone maximum and one minimum value
- Done maximum and one minimum value
Correct answer
C. one maximum and one minimum value
Step-by-step solution
Given, f(x)=x^3+a x^2+b x+c, a^2 3 b . On differentiating w.r.t. x , we get aligned & f^ (x)=3 x^2+2 a x+b & Put f^ (x)=0 & 3 x^2+2 a x+b=0 & aligned aligned x & = -2 a 4 a^2-12 b 2 3 & = -2 a 2 a^2-3 b 3 aligned Since, a^2 3 b , x has an imaginary value. Hence, no extreme value of x exist.