Math Problem Statement

answer

Suppose g(x) = ∫₀ˣ (7 + √t) dt. Calculate g'(x) in two different ways: 1. Using Part 1 of the Fundamental Theorem of Calculus. 2. Using Part 2 of the Fundamental Theorem of Calculus to evaluate the integral, then differentiate.

Solution

Let's work through this problem using the Fundamental Theorem of Calculus (FTC), which has two parts:

  1. Part 1 of the Fundamental Theorem of Calculus: This part states that if g(x)=axf(t)dtg(x) = \int_a^x f(t) \, dt, then g(x)=f(x)g'(x) = f(x). This is the derivative of the integral function.

  2. Part 2 of the Fundamental Theorem of Calculus: This part states that if F(x)F(x) is an antiderivative of f(x)f(x), then abf(x)dx=F(b)F(a)\int_a^b f(x) \, dx = F(b) - F(a).

Now, let's solve this step by step.

1. Use Part 1 of the Fundamental Theorem of Calculus to find g(x)g'(x)

Given: g(x)=0x(7+t)dtg(x) = \int_0^x \left( 7 + \sqrt{t} \right) \, dt

Using Part 1 of the Fundamental Theorem of Calculus, we differentiate the integral with respect to xx. This gives:

g(x)=7+xg'(x) = 7 + \sqrt{x}

2. Use Part 2 of the Fundamental Theorem of Calculus to evaluate g(x)g(x)

We need to evaluate the integral directly:

g(x)=0x(7+t)dtg(x) = \int_0^x \left( 7 + \sqrt{t} \right) \, dt

This can be split into two integrals:

g(x)=0x7dt+0xtdtg(x) = \int_0^x 7 \, dt + \int_0^x \sqrt{t} \, dt

Now, evaluate both integrals:

  • The integral of 7dt7 \, dt is 7x7x,
  • The integral of tdt\sqrt{t} \, dt is 23t3/2\frac{2}{3} t^{3/2}, so at the limits 00 to xx, it becomes 23x3/2\frac{2}{3} x^{3/2}.

Thus, we get:

g(x)=7x+23x3/2g(x) = 7x + \frac{2}{3} x^{3/2}

3. Now differentiate your answer for g(x)g(x)

Now we differentiate g(x)=7x+23x3/2g(x) = 7x + \frac{2}{3} x^{3/2} with respect to xx:

g(x)=ddx(7x+23x3/2)=7+2332x1/2=7+xg'(x) = \frac{d}{dx} \left( 7x + \frac{2}{3} x^{3/2} \right) = 7 + \frac{2}{3} \cdot \frac{3}{2} x^{1/2} = 7 + \sqrt{x}

Conclusion:

  • Using Part 1 of the Fundamental Theorem of Calculus, g(x)=7+xg'(x) = 7 + \sqrt{x}.
  • Using Part 2, we evaluated g(x)=7x+23x3/2g(x) = 7x + \frac{2}{3} x^{3/2}, and differentiating this gives g(x)=7+xg'(x) = 7 + \sqrt{x}.

Do you want more details or have any questions?


Here are 5 related questions to deepen your understanding:

  1. How does the Fundamental Theorem of Calculus relate differentiation and integration?
  2. Can you explain why the upper limit of the integral affects the result in Part 1 of the FTC?
  3. How would the answer change if the lower limit of the integral were a function of xx rather than 0?
  4. What is the significance of the constant when evaluating an indefinite integral?
  5. How would you compute g(x)g(x) if the integrand was more complex, like a trigonometric function?

Tip: Always check your results by differentiating the antiderivative to ensure consistency.

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Math Problem Analysis

Mathematical Concepts

Calculus
Definite Integrals
Derivatives

Formulas

g'(x) = f(x) (from Part 1 of the Fundamental Theorem of Calculus)
g(x) = F(b) - F(a) (from Part 2 of the Fundamental Theorem of Calculus)
Derivative of a sum: (f + g)' = f' + g'

Theorems

Fundamental Theorem of Calculus (Part 1 and Part 2)

Suitable Grade Level

College Calculus