a)Find the equation of the tangent at the point (t,$\displaystyle t^3$) on the curve $\displaystyle y=x^3$.Find also the coordinates of the point where this tangent meets the curve again.

b) For the curve, $\displaystyle y=(4/x^2)+x$ , show the following ,

i) the entire curve lies above the line y=x

Red colour fonts are parts which I need help, thanks in advance!