A plane curve whose equation is $y - f (x) = 0$ passes through the origin.Consider the rectangle $R_x$ formed by the coordinate axes and lines parallel to the axis passing through the point $(x, f (x))$ of the curve lines. If the curve divides the rectangle into two regions and one of the area of the region is 10 times the area of the other.
How can I find $f$.I stuck in this exercise some help please.
Area of rectangle : $x\times f(x)$
One part of area: $\int_0^x f(x) dx$.
Can you do it now?