Questions: Evaluate
[
intc 4 x^2 d x
]
c is a line segment joining (0,2) to (2,0)
Transcript text: Evaluate
\[
\int_{c} 4 x^{2} d x \quad \begin{array}{l}
c \text { is a line segment } \\
\text { joining }(0,2) \text { to }(2,0)
\end{array}
\]
Solution
Solution Steps
Solution Approach
Parameterize the line segment joining (0,2) to (2,0).
Express \( x \) and \( y \) in terms of a parameter \( t \) that varies from 0 to 1.
Substitute these parameterized expressions into the integral.
Evaluate the resulting integral with respect to \( t \).
Step 1: Parameterization of the Line Segment
The line segment joining the points \((0, 2)\) and \((2, 0)\) can be parameterized using the variable \(t\) as follows:
\[
x = 2t, \quad y = 2 - 2t \quad \text{for } t \in [0, 1].
\]
Step 2: Calculation of \(dx/dt\)
To evaluate the integral, we need to compute the derivative of \(x\) with respect to \(t\):
\[
\frac{dx}{dt} = 2.
\]
Step 3: Formulation of the Integrand
Substituting the parameterization into the integrand \(4x^2 \, dx\), we have:
\[
\text{Integrand} = 4(2t)^2 \cdot 2 = 32t^2.
\]
Step 4: Evaluation of the Integral
Now, we evaluate the integral:
\[
\int_{0}^{1} 32t^2 \, dt.
\]
Calculating this gives:
\[
\int_{0}^{1} 32t^2 \, dt = \left[ \frac{32}{3} t^3 \right]_{0}^{1} = \frac{32}{3}.
\]
Final Answer
The value of the integral is
\[
\boxed{\frac{32}{3}}.
\]