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Let 
f(x)=-4x^(3)+6x^(2)-5.
The absolute minimum value of 
f over the closed interval 
-2 <= x <= 3 occurs at what 
x value?
Choose 1 answer:
(A) -2
(B) 3
(C) 0
(D) 1

Let f(x)=4x3+6x25 f(x)=-4 x^{3}+6 x^{2}-5 .\newlineThe absolute minimum value of f f over the closed interval 2x3 -2 \leq x \leq 3 occurs at what x x value?\newlineChoose 11 answer:\newline(A) 2-2\newline(B) 33\newline(C) 00\newline(D) 11

Full solution

Q. Let f(x)=4x3+6x25 f(x)=-4 x^{3}+6 x^{2}-5 .\newlineThe absolute minimum value of f f over the closed interval 2x3 -2 \leq x \leq 3 occurs at what x x value?\newlineChoose 11 answer:\newline(A) 2-2\newline(B) 33\newline(C) 00\newline(D) 11
  1. Find Critical Points: To find the absolute minimum value of the function on the closed interval [2,3][-2, 3], we first need to find the critical points of the function within the interval. Critical points occur where the derivative of the function is zero or undefined.
  2. Calculate Derivative: We calculate the derivative of f(x)=4x3+6x25f(x) = -4x^3 + 6x^2 - 5.f(x)=ddx(4x3+6x25)=12x2+12xf'(x) = \frac{d}{dx} (-4x^3 + 6x^2 - 5) = -12x^2 + 12x.
  3. Find Critical Points: Next, we find the critical points by setting the derivative equal to zero and solving for xx.12x2+12x=0-12x^2 + 12x = 0x(12x+12)=0x(-12x + 12) = 0x=0x = 0 or x=1x = 1.
  4. Evaluate Function: We now have two critical points, x=0x = 0 and x=1x = 1, within the interval [2,3][-2, 3]. We also need to evaluate the function at the endpoints of the interval, which are x=2x = -2 and x=3x = 3.
  5. Compare Values: We evaluate the function at the critical points and the endpoints:\newlinef(2)=4(2)3+6(2)25=4(8)+6(4)5=32+245=51f(-2) = -4(-2)^3 + 6(-2)^2 - 5 = -4(-8) + 6(4) - 5 = 32 + 24 - 5 = 51.\newlinef(0)=4(0)3+6(0)25=5f(0) = -4(0)^3 + 6(0)^2 - 5 = -5.\newlinef(1)=4(1)3+6(1)25=4+65=3f(1) = -4(1)^3 + 6(1)^2 - 5 = -4 + 6 - 5 = -3.\newlinef(3)=4(3)3+6(3)25=4(27)+6(9)5=108+545=59f(3) = -4(3)^3 + 6(3)^2 - 5 = -4(27) + 6(9) - 5 = -108 + 54 - 5 = -59.
  6. Absolute Minimum Value: Comparing the values of f(x)f(x) at the critical points and endpoints, we find that the absolute minimum value occurs at x=1x = 1, since f(1)=3f(1) = -3 is the smallest value.
  7. Absolute Minimum Value: Comparing the values of f(x)f(x) at the critical points and endpoints, we find that the absolute minimum value occurs at x=1x = 1, since f(1)=3f(1) = -3 is the smallest value.The answer to the question prompt is that the absolute minimum value of the function f(x)=4x3+6x25f(x) = -4x^3 + 6x^2 - 5 over the interval [2,3][-2, 3] occurs at x=1x = 1.

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