Tangent curve y = disposed in the first quadrant to any of the f (x) point P (x, y) is equal to the inverse of discovery intercept on the y-intercept of the x-axis, and the curve after ( 1,0), the demand curve

High Differential Number Title: set the first quadrant is located in the curve y = any point P (x, y) on the f (x) is equal to the tangent point opposite to the y-axis intercept found in the x-axis intercept number, and after the curve (1,0), the demand curve.