Find the area of the region bounded by the curves y2=4xy^2 = 4x and x2=4yx^2 = 4y.

Answer: The area of the region bounded by the curves y2=4xy^2 = 4x and x2=4yx^2 = 4y is 163\frac{16}{3} square units.

Step-by-step solution

Step 1: Identify the curves and find intersection points

We are given two parabolic equations. To find the area bounded by them, we first need to determine their points of intersection. We will solve these equations simultaneously to find the (x,y)(x, y) coordinates where they intersect.

Step 2: Substitute y from (2) into (1)

From equation (2), we can express yy as y=x24y = \frac{x^2}{4}. Substitute this expression for yy into equation (1) to eliminate yy and obtain an equation solely in terms of xx.

Step 3: Solve for x-coordinates of intersection

Simplify the equation to solve for xx. Factor out xx from the equation x4−64x=0x^4 - 64x = 0. This gives us two possibilities for xx: x=0x=0 or x3−64=0x^3 - 64 = 0.

Step 4: Find the values of x

From x(x3−64)=0x(x^3 - 64) = 0, we get x=0x=0 as one solution. For the second solution, we solve x3=64x^3 = 64, which yields x=4x=4 since 43=644^3 = 64. These are the xx -coordinates of the intersection points.

Step 5: Find the y-coordinates of intersection

Substitute the xx -values back into either equation (1) or (2) to find the corresponding yy -coordinates. Using y=x24y = \frac{x^2}{4} (from equation 2), we find that when x=0x=0, y=0y=0, and when x=4x=4, y=4y=4. Thus, the curves intersect at (0,0)(0{,}0) and (4,4)(4{,}4).

Step 6: Set up the integral for the area

To find the area enclosed by the two curves, we integrate the difference between the upper curve and the lower curve with respect to xx, from the first intersection point to the second. In this region, y2=4xy^2=4x means y=2xy = 2\sqrt{x} (upper half) and x2=4yx^2=4y means y=x24y = \frac{x^2}{4} (lower curve). We need to determine which curve is 'upper' and which is 'lower' in the interval [0,4][0{,}4].

Step 7: Determine upper and lower curves

From y2=4xy^2=4x, we get y=±2xy = \pm 2\sqrt{x}. Since the region of interest is in the first quadrant (between x=0x=0 and x=4x=4), we consider the positive root, y1=2xy_1 = 2\sqrt{x}. From x2=4yx^2=4y, we get y2=x24y_2 = \frac{x^2}{4}. We observe that for x∈(0,4)x \in (0{,}4), 2x>x242\sqrt{x} > \frac{x^2}{4}. For example, at x=1x=1, 21=22\sqrt{1} = 2 and 124=0.25\frac{1^2}{4} = 0.25. So, y1=2xy_1 = 2\sqrt{x} is the upper curve and y2=x24y_2 = \frac{x^2}{4} is the lower curve.

Step 8: Integrate to find the area

Now we set up the definite integral with the limits of integration from x=0x=0 to x=4x=4 and the integrand as the difference between the upper curve y=2xy=2\sqrt{x} and the lower curve y=x24y=\frac{x^2}{4}.

Step 9: Perform the integration

Integrate each term with respect to xx. Recall that ∫xndx=xn+1n+1\int x^n dx = \frac{x^{n+1}}{n+1}. So, ∫xdx=∫x1/2dx=x3/23/2\int \sqrt{x} dx = \int x^{1/2} dx = \frac{x^{3/2}}{3/2} and ∫x2dx=x33\int x^2 dx = \frac{x^3}{3}.

Step 10: Simplify the integrated terms

Simplify the constants. 2⋅13/2=2⋅23=432 \cdot \frac{1}{3/2} = 2 \cdot \frac{2}{3} = \frac{4}{3} and 14⋅13=112\frac{1}{4} \cdot \frac{1}{3} = \frac{1}{12}.

Step 11: Evaluate the definite integral

Apply the limits of integration by substituting the upper limit (x=4x=4) and the lower limit (x=0x=0) into the integrated expression and subtracting the result for the lower limit from the result for the upper limit.

Step 12: Calculate the numerical value

Calculate the values: 43/2=(4)3=23=84^{3/2} = (\sqrt{4})^3 = 2^3 = 8. Simplify 6412\frac{64}{12} by dividing both numerator and denominator by 4 to get 163\frac{16}{3}. Subtract the terms.

Step 13: Final calculation

Perform the final subtraction to get the area.

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