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For the function f(x)=2x3−9x2+12x−5f(x) = 2x^3 - 9x^2 + 12x - 5, x∈[0,3]x \in [0, 3], match List-I with List-II :

List-IList-II
A. Absolute maximum value(I) 33
B. Absolute minimum value(II) 00
C. Point of maxima(III) −5-5
D. Point of minima(IV) 44

Solution

✅ Correct Option: 4

To find absolute max/min on a closed interval, we need to evaluate f(x)f(x) at all critical points and endpoints.


Find critical points by setting f′(x)=0f'(x) = 0:

f′(x)=6x2−18x+12=0f'(x) = 6x^2 - 18x + 12 = 0

x2−3x+2=0x^2 - 3x + 2 = 0

(x−1)(x−2)=0(x - 1)(x - 2) = 0

x=1x = 1 and x=2x = 2

Both lie within [0,3][0, 3], so both are valid.


Evaluate f(x)f(x) at x=0,1,2,3x = 0, 1, 2, 3:

f(0)=2(0)3−9(0)2+12(0)−5=−5f(0) = 2(0)^3 - 9(0)^2 + 12(0) - 5 = -5

f(1)=2(1)3−9(1)2+12(1)−5=2−9+12−5=0f(1) = 2(1)^3 - 9(1)^2 + 12(1) - 5 = 2 - 9 + 12 - 5 = 0

f(2)=2(8)−9(4)+12(2)−5=16−36+24−5=−1f(2) = 2(8) - 9(4) + 12(2) - 5 = 16 - 36 + 24 - 5 = -1

f(3)=2(27)−9(9)+12(3)−5=54−81+36−5=4f(3) = 2(27) - 9(9) + 12(3) - 5 = 54 - 81 + 36 - 5 = 4


From these values:

  • Absolute maximum value =4= 4, occurring at x=3x = 3 (point of maxima)
  • Absolute minimum value =−5= -5, occurring at x=0x = 0 (point of minima)

Note: Even though x=1x = 1 and x=2x = 2 are critical points, the function reaches its highest and lowest values at the endpoints of the interval. This is why we always check endpoints on a closed interval.


A →\to (IV), B →\to (III), C →\to (I), D →\to (II)

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