Math Problem Statement

Given g(x) = ∫(from 2 to x) t^4 dt, find dg/dx using the Fundamental Theorem of Calculus, part 1, and then differentiate.

Solution

The given problem involves using the Fundamental Theorem of Calculus to evaluate and differentiate an integral. Here's the breakdown of the solution:

Problem Statement:

Given g(x)=2xt4dtg(x) = \int_{2}^{x} t^4 \, dt, we are tasked to:

  1. Find ddxg(x)\frac{d}{dx} g(x).
  2. Use the Fundamental Theorem of Calculus, evaluate the integral, and then differentiate it.

Solution:

1. Directly Differentiating g(x)g(x):

By the Fundamental Theorem of Calculus (Part 1), the derivative of the integral is given by:

ddxaxf(t)dt=f(x),\frac{d}{dx} \int_{a}^{x} f(t) \, dt = f(x),

where f(t)f(t) is the integrand.

Here, f(t)=t4f(t) = t^4, so:

ddxg(x)=x4.\frac{d}{dx} g(x) = x^4.


2. Evaluate the Integral, Then Differentiate:

The integral g(x)g(x) can be evaluated explicitly:

g(x)=2xt4dt.g(x) = \int_{2}^{x} t^4 \, dt.

To compute this:

t4dt=t55+C.\int t^4 \, dt = \frac{t^5}{5} + C.

Applying the limits 22 to xx:

[ g(x) = \left[\frac{x^5}{5}\right] - \left[\frac{2^5}{5}\right] = \frac{x^5}{5} - \frac{32}{5}. ]

Now, differentiate g(x)g(x):

ddxg(x)=ddx(x55325)=5x45=x4.\frac{d}{dx} g(x) = \frac{d}{dx} \left( \frac{x^5}{5} - \frac{32}{5} \right) = \frac{5x^4}{5} = x^4.


Final Answer:

ddxg(x)=x4.\frac{d}{dx} g(x) = x^4.

Both methods confirm the result.


Do you want further clarification or additional examples? Here are 5 related questions for practice:

  1. What is the derivative of g(x)=1xsin(t)dtg(x) = \int_{1}^{x} \sin(t) \, dt?
  2. If g(x)=3x(2t+1)dtg(x) = \int_{3}^{x} (2t + 1) \, dt, find g(x)g'(x).
  3. Evaluate 0xetdt\int_{0}^{x} e^t \, dt and then differentiate it.
  4. Explain the difference between Fundamental Theorem of Calculus Part 1 and Part 2.
  5. Solve ddxx4cos(t)dt\frac{d}{dx} \int_{x}^{4} \cos(t) \, dt.

Tip: Always verify the limits of integration when applying the Fundamental Theorem of Calculus!

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Math Problem Analysis

Mathematical Concepts

Integral Calculus
Differentiation
Fundamental Theorem of Calculus

Formulas

d/dx ∫(from a to x) f(t) dt = f(x)
∫ t^n dt = t^(n+1)/(n+1) + C

Theorems

Fundamental Theorem of Calculus, Part 1

Suitable Grade Level

Grades 11-12 or early college