Question

express the following shaded area using a definite integral. use geometry to calculate the area. please show work too

Answer 1

Answer:

Integrate( sqrt(9-x^2) from x=-3 to x=3)

Step-by-step explanation:

The equation for a full circle is (x-h)^2+(y-k)^2=r^2 where (h,k) is center and radius is r.

Your center, your (h,k) is (0,0). Your radius, your r, is 3.

So your equation is (x-0)^2+(y-0)^2=3^2 or more simply x^2+y^2=9.

We also must consider we don't have full circle.

Solving for y will give us the circle in terms of top half if we take positive values and bottom half if we take negative values. Since y is positive in the picture, you only see top half, we will only take the positive cases for y.

Subtracting x^2 on both sides gives: y^2=9-x^2

Square root both sides: y= sqrt(9-x^2)

(I did not choose -sqrt(9-x^2) because again y is positive).

So the x's in the picture range from -3 to 3.

The integral is therefore,

Integrate( sqrt(9-x^2) from x=-3 to x=3)