AP EAMCET2007MathematicsApplication of Derivatives
The condition f(x)=x^3+p x^2+q x+r(x R) to have no extreme value, is
Options
- Ap^2 < 3 q
- B2 p^2 < q
- Cp^2 < 1 4 q
- Dp^2>3 q
Correct answer
A. p^2 < 3 q
Step-by-step solution
Given, f(x)=x^3+p x^2+q x+r Now, f^ (x)=3 x^2+2 x p+q Clearly f^ (x)>0 Now, b^2-4 a c < 0 4 p^2-4 3 q < 0 array rrr & 4 p^2-12 q < 0 & p^2 < 3 q array