Find the area of the region bounded by y2=9x, x=2, x=4 and the x-axis in the first quadrant.

The area of the region bounded by the curve,y2=9x,x=2,and x=4,and the x-axis is the area ABCD.
Area of ABCD =\(\int^4_2ydx\)
=\(\int^4_2\sqrt xdx\)
=\(3\bigg[\frac{x^{\frac{3}{2}}}{\frac{3}{2}}\bigg]\)
=\(2\bigg[x^{\frac{3}{2}}\bigg]^4_2\)
=\(2\bigg[(4)^{\frac{3}{2}}-(2)^{\frac{3}{2}}\bigg]\)
=\(2[8-2\sqrt2]\)
=(16-4\(\sqrt2\)) units.
Let \( f : (0, \infty) \to \mathbb{R} \) be a twice differentiable function. If for some \( a \neq 0 \), } \[ \int_0^a f(x) \, dx = f(a), \quad f(1) = 1, \quad f(16) = \frac{1}{8}, \quad \text{then } 16 - f^{-1}\left( \frac{1}{16} \right) \text{ is equal to:}\]

The representation of the area of a region under a curve is called to be as integral. The actual value of an integral can be acquired (approximately) by drawing rectangles.
Also, F(x) is known to be a Newton-Leibnitz integral or antiderivative or primitive of a function f(x) on an interval I.
F'(x) = f(x)
For every value of x = I.
Integral calculus helps to resolve two major types of problems: