For finding absolute maximum and minimum values of a function f gives by $f(x)=2x^3-15x^2+36x + 1 $ on [1, 5]. A. the critical points in (1, 5) are 2 and 3. B. the absolute maximum value of f on [1, 5] is 29. C. the absolute minimum value of f on [1, 5] is 24. D. the absolute minimum values of f on [1, 5] is 20. E. we evaluate the value of f at critical points and at the end points of the interval [1, 5]. Choose the correct answer from the options given below : |
A, C, E only D, E only B, C, D only C, D, E only |
A, C, E only |
The correct answer is Option (1) → A, C, E only $f(x)=2x^3-15x^2+36x + 1$, $x∈[1, 5]$ $f'(x)=6x^2-30x+36=0$ $x^2-5x+6=0$ $(x-2)(x-3)=0⇒x=2,3$ critical points so $f(1)=2-15+36+1=24$ $f(2)=2×2^3-15×2^2+36×2+1=29$ $f(3)=2×3^3-15×3^2+36×3+1=28$ $f(5)=2×5^3-15×5^2+36×5+1=56$ |