We all know that finding the area of a triangle is easy, right Its just base times height 1/2 * b * h,
and if those measurements are in centimeters, the area is in square centimeters. But what
happens when you have something curvy Theres no straightforward formula for that.
Thats where integration comes in. The core idea is to break down the irregular shape into a
bunch of tiny rectangles. Imagine slicing that curvy area into a grid of very narrow rectangles.
Lets visually think about it. Imagine a plot here with a curvy line and a bunch of rectangles
underneath, progressively smaller.
Now, for each rectangle, we can calculate its area. The width of each rectangle is incredibly
small were talking h, nearly zero which is key to the whole concept.
Lets say our curve is defined by a function fx. If were considering a particular rectangle, lets say
it sits at a position x = a + kh*, where k represents a specific rectangle in our grid, and h is the
extremely small width.
The length of that rectangle is essentially the value of the function fx at that x-value, so its fa +
kh.
So, the area of one rectangle is simply width * length = h * fa + kh.
And to get the total area under the curve, we essentially sum the areas of all those tiny
rectangles. Thats the heart of integration Varying k allows us to account for all the rectangles
making up the area.
Its like saying, If I have a bunch of really, really skinny rectangles that cover the area under the
curve, the sum of their areas will get closer and closer to the true area as each rectangle
becomes even skinnier. And thats integration in a nutshell.