Can y = 1 / X be defined as a definite integral? How to integrate [1,2] if it is over energy Can y = √ (1-x ^ 2) be used for definite integral [- 1,1] without geometric meaning? Is it possible to use definition method for integral?

Can y = 1 / X be defined as a definite integral? How to integrate [1,2] if it is over energy Can y = √ (1-x ^ 2) be used for definite integral [- 1,1] without geometric meaning? Is it possible to use definition method for integral?

It is difficult to estimate the definite integral of y = 1 / X by definition method. Y = √ (1-x ^ 2) can be used for definite integral [- 1,1] without geometric meaning. The original function of y = √ (1-x ^ 2) is 1 / 2x √ (1-x ^ 2) + 1 / 2arcsinx + C, and then Newton Leibniz formula is used. It may be difficult to use definition method