For the function [tex]f(x) = 4x^4 - 3x^3 - 3x^2 + 7[/tex], find [tex]f''(x)[/tex]. Then find [tex]f''(0)[/tex] and [tex]f''(8)[/tex].

[tex]f''(x) =[/tex]



Answer :

Sure, let's go through the process of finding the second derivative of the function [tex]\( f(x) = 4x^4 - 3x^3 - 3x^2 + 7 \)[/tex]. Then, we will evaluate the second derivative at [tex]\( x = 0 \)[/tex] and [tex]\( x = 8 \)[/tex].

1. First Derivative:
We start by finding the first derivative [tex]\( f'(x) \)[/tex] of the function [tex]\( f(x) \)[/tex].

[tex]\[ f(x) = 4x^4 - 3x^3 - 3x^2 + 7 \][/tex]

To find [tex]\( f'(x) \)[/tex], we differentiate [tex]\( f(x) \)[/tex] with respect to [tex]\( x \)[/tex]:

[tex]\[ f'(x) = \frac{d}{dx}(4x^4 - 3x^3 - 3x^2 + 7) \][/tex]

Using the power rule [tex]\( \left(\frac{d}{dx} x^n = nx^{n-1}\right) \)[/tex], we get:

[tex]\[ f'(x) = 16x^3 - 9x^2 - 6x \][/tex]

2. Second Derivative:
Next, we need to find the second derivative [tex]\( f''(x) \)[/tex] by differentiating [tex]\( f'(x) \)[/tex]:

[tex]\[ f'(x) = 16x^3 - 9x^2 - 6x \][/tex]

Differentiate [tex]\( f'(x) \)[/tex] with respect to [tex]\( x \)[/tex]:

[tex]\[ f''(x) = \frac{d}{dx}(16x^3 - 9x^2 - 6x) \][/tex]

Again, applying the power rule:

[tex]\[ f''(x) = 48x^2 - 18x - 6 \][/tex]

Therefore, the second derivative of the function [tex]\( f(x) \)[/tex] is:

[tex]\[ f''(x) = 48x^2 - 18x - 6 \][/tex]

3. Evaluating [tex]\( f''(0) \)[/tex]:
To find [tex]\( f''(0) \)[/tex], we substitute [tex]\( x = 0 \)[/tex] into [tex]\( f''(x) \)[/tex]:

[tex]\[ f''(0) = 48(0)^2 - 18(0) - 6 = -6 \][/tex]

4. Evaluating [tex]\( f''(8) \)[/tex]:
To find [tex]\( f''(8) \)[/tex], we substitute [tex]\( x = 8 \)[/tex] into [tex]\( f''(x) \)[/tex]:

[tex]\[ f''(8) = 48(8)^2 - 18(8) - 6 \][/tex]

Calculate each term separately:

[tex]\[ 48(8)^2 = 48 \times 64 = 3072 \][/tex]

[tex]\[ 18(8) = 144 \][/tex]

Substite these values into [tex]\( f''(8) \)[/tex]:

[tex]\[ f''(8) = 3072 - 144 - 6 = 2922 \][/tex]

So, the second derivative is:

[tex]\[ f''(x) = 48x^2 - 18x - 6 \][/tex]

And the specific evaluations are:

[tex]\[ f''(0) = -6 \][/tex]

[tex]\[ f''(8) = 2922 \][/tex]