Maths
Area Under Curve
Area Bounded by Straight Line and Curve
The area (in square units) bounded by the curve $y=2x-x^2$ and the straight line $y=-x$ is:
Answer Review
First, equate the equations to determine their points of intersection:
$2x-x^2=-x$
$\Rightarrow 3x-x^2=0$
$\Rightarrow x(3-x)=0$
Therefore, $x=0$ or $x=3$.
For $0\leq x\leq3$, the curve $y=2x-x^2$ lies above the line $y=-x$.
Therefore, the required area is:
$A=\int_0^3\left[(2x-x^2)-(-x)\right],dx$
$A=\int_0^3(3x-x^2),dx$
$A=\left[\frac{3x^2}{2}-\frac{x^3}{3}\right]_0^3$
$A=\left(\frac{3(3)^2}{2}-\frac{(3)^3}{3}\right)-0$
$A=\frac{27}{2}-9$
$A=\frac{27-18}{2}$
$A=\frac{9}{2}$
Hence, the area bounded by the given curve and line is $\frac{9}{2}$ square units.
$2x-x^2=-x$
$\Rightarrow 3x-x^2=0$
$\Rightarrow x(3-x)=0$
Therefore, $x=0$ or $x=3$.
For $0\leq x\leq3$, the curve $y=2x-x^2$ lies above the line $y=-x$.
Therefore, the required area is:
$A=\int_0^3\left[(2x-x^2)-(-x)\right],dx$
$A=\int_0^3(3x-x^2),dx$
$A=\left[\frac{3x^2}{2}-\frac{x^3}{3}\right]_0^3$
$A=\left(\frac{3(3)^2}{2}-\frac{(3)^3}{3}\right)-0$
$A=\frac{27}{2}-9$
$A=\frac{27-18}{2}$
$A=\frac{9}{2}$
Hence, the area bounded by the given curve and line is $\frac{9}{2}$ square units.