1. **State the problem:** Find the area enclosed by the curves given by the equations:
$$2y=5\sqrt{x}, \quad y=5, \quad 2y+3x=8$$
2. **Rewrite each equation in terms of $y$ or $x$ for clarity:**
- From $2y=5\sqrt{x}$, we get $$y=\frac{5}{2}\sqrt{x}$$
- The second curve is $$y=5$$
- From $2y+3x=8$, solve for $y$:
$$2y=8-3x \implies y=\frac{8-3x}{2}$$
3. **Find the points of intersection to determine the limits of integration:**
- Intersection of $y=5$ and $y=\frac{5}{2}\sqrt{x}$:
$$5=\frac{5}{2}\sqrt{x} \implies 5=\frac{5}{2}\sqrt{x}$$
Divide both sides by 5:
$$\cancel{5}=\frac{\cancel{5}}{2}\sqrt{x} \implies 1=\frac{1}{2}\sqrt{x}$$
Multiply both sides by 2:
$$2=\sqrt{x}$$
Square both sides:
$$4=x$$
So, intersection point is at $x=4$, $y=5$.
- Intersection of $y=5$ and $y=\frac{8-3x}{2}$:
$$5=\frac{8-3x}{2}$$
Multiply both sides by 2:
$$10=8-3x$$
Subtract 8:
$$10-8=-3x \implies 2=-3x$$
Divide both sides by $-3$:
$$\frac{2}{-3}=-x \implies x=-\frac{2}{3}$$
Since $x$ cannot be negative for the first curve (due to square root), this intersection is outside the domain of interest.
- Intersection of $y=\frac{5}{2}\sqrt{x}$ and $y=\frac{8-3x}{2}$:
Set equal:
$$\frac{5}{2}\sqrt{x} = \frac{8-3x}{2}$$
Multiply both sides by 2:
$$5\sqrt{x} = 8 - 3x$$
Rearranged:
$$5\sqrt{x} + 3x = 8$$
Let $t=\sqrt{x}$, so $x=t^2$:
$$5t + 3t^2 = 8$$
Rewrite:
$$3t^2 + 5t - 8 = 0$$
Solve quadratic:
$$t = \frac{-5 \pm \sqrt{5^2 - 4 \cdot 3 \cdot (-8)}}{2 \cdot 3} = \frac{-5 \pm \sqrt{25 + 96}}{6} = \frac{-5 \pm \sqrt{121}}{6}$$
$$t = \frac{-5 \pm 11}{6}$$
Two solutions:
- $$t = \frac{-5 + 11}{6} = 1$$
- $$t = \frac{-5 - 11}{6} = -\frac{16}{6} = -\frac{8}{3}$$ (discard negative since $t=\sqrt{x} \geq 0$)
So, $t=1 \implies x=1$.
4. **Determine the area enclosed:**
The region is bounded between $x=1$ and $x=4$.
- The upper curve is $y=5$.
- The lower curve is $y=\frac{5}{2}\sqrt{x}$ from $x=1$ to $x=4$.
5. **Set up the integral for the area:**
$$\text{Area} = \int_1^4 \left(5 - \frac{5}{2}\sqrt{x}\right) dx$$
6. **Calculate the integral:**
$$\int_1^4 5 dx = 5x \Big|_1^4 = 5(4) - 5(1) = 20 - 5 = 15$$
$$\int_1^4 \frac{5}{2} \sqrt{x} dx = \frac{5}{2} \int_1^4 x^{1/2} dx = \frac{5}{2} \cdot \frac{2}{3} x^{3/2} \Big|_1^4 = \frac{5}{3} (4^{3/2} - 1^{3/2})$$
Calculate $4^{3/2}$:
$$4^{3/2} = (\sqrt{4})^3 = 2^3 = 8$$
So:
$$\frac{5}{3} (8 - 1) = \frac{5}{3} \times 7 = \frac{35}{3}$$
7. **Subtract to find the area:**
$$15 - \frac{35}{3} = \frac{45}{3} - \frac{35}{3} = \frac{10}{3}$$
**Final answer:**
$$\boxed{\frac{10}{3}}$$
This is the area enclosed by the curves.
Area Enclosed C3571D
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