asked 33.5k views
1 vote
Given f ′′

(x)=8x 2
−8x 3
+10x+7,f ′
(1)=−8, and f(1)=−4 Find f ′
(x) and f(x). Part 1: Find the anti-derivative of f ′′
(x). C 1

for f ′
(x) f ′
(x)= Part 2: Find the anti-derivative for f ′
(x). C 2

for f(x)=
f(x)=

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asked
User Jwkoo
by
8.2k points

1 Answer

3 votes

Answer:

Sure, let's solve this problem step by step.

Part 1: Find the anti-derivative of f''(x) to get f'(x).

To find the anti-derivative of f''(x), you need to integrate it with respect to x:

∫f''(x) dx = ∫(8x^2 - 8x^3 + 10x + 7) dx

Now, let's find the anti-derivative term by term:

∫8x^2 dx = (8/3)x^3 + C₁, where C₁ is the constant of integration for this term.

∫-8x^3 dx = (-8/4)x^4 + C₁ = -2x^4 + C₁

∫10x dx = 5x^2 + C₁

∫7 dx = 7x + C₁

Now, sum up all these anti-derivative terms:

f'(x) = (8/3)x^3 - 2x^4 + 5x^2 + 7x + C₁

Part 2: Find the anti-derivative for f'(x) to get f(x).

To find the anti-derivative of f'(x), you need to integrate it with respect to x:

∫f'(x) dx = ∫[(8/3)x^3 - 2x^4 + 5x^2 + 7x + C₁] dx

Now, let's find the anti-derivative term by term:

∫(8/3)x^3 dx = (8/12)x^4 + C₂ = (2/3)x^4 + C₂, where C₂ is the constant of integration for this term.

∫(-2x^4) dx = (-2/5)x^5 + C₂

∫5x^2 dx = (5/3)x^3 + C₂

∫7x dx = (7/2)x^2 + C₂

∫C₁ dx = C₁x + C₂

Now, sum up all these anti-derivative terms:

f(x) = (2/3)x^4 - (2/5)x^5 + (5/3)x^3 + (7/2)x^2 + C₁x + C₂

You now have the anti-derivative of f'(x) with the constants of integration C₁ and C₂. To determine the values of C₁ and C₂, you can use the initial conditions given:

f'(1) = -8 and f(1) = -4

Plug in x = 1 into the expressions for f'(x) and f(x), and set them equal to the given values:

f'(1) = (8/3)(1)^3 - 2(1)^4 + 5(1)^2 + 7(1) + C₁ = -8

f(1) = (2/3)(1)^4 - (2/5)(1)^5 + (5/3)(1)^3 + (7/2)(1)^2 + C₁(1) + C₂ = -4

Now, you can solve this system of equations for C₁ and C₂.

Explanation:

answered
User SofaKng
by
8.2k points
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