Please help me explain in detail what integral is. Mathematical terms. thank you

The concept of integral:

Draw a circle (radius 10cm) on a piece of drawing paper, and the small square of the drawing paper is 1cm× 1cm, and estimate the area of the circle;

The square of the drawing paper is 0. 1cm× 0. 1cm, and the area of the circle is estimated.

The square of the drawing paper is 0.00 1cm×0.00 1cm, and the area of the circle is estimated;

The square of the drawing paper is 0.00001cm× 0.00001cm, and the area of the circle is estimated;

The square of the drawing paper is 0.0000001cm× 0.000001cm, and the area of the circle is estimated;

The square of the drawing paper is 0.000000001cm× 0.0000001cm, and the area of the circle is estimated;

The square of the drawing paper is 0.0000000001cm× 0.00000001cm, and the area of the circle is estimated;

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This estimate is getting more and more accurate.

Divide a curve into 10 segments and add up the linear distance of each segment;

Divide the curve into 100 segments, and add the straight line distances of each segment;

Divide the curve into 10000 segments, and add the straight line distances of each segment;

Divide the curve into 1000000 segments, and add the straight line distances of each segment;

Divide the curve into 10000000 segments, and add the straight line distances of each segment;

Divide the curve into 1000000000 segments, and add the straight line distances of each segment;

Divide the curve into 1000000000000 segments, and add the straight line distances of each segment;

Divide the curve into/kloc-0 1000000000000000 segments, and add the straight line distances of each segment;

Divide the curve into/kloc-0 1000000000000000000 segments, and add the straight line distances of each segment;

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The length thus calculated is more and more accurate as the length of the curve.

The above two examples are the whole idea;

A set of accurate calculation methods established from this is integration.

Differential+integral = calculus