Let y = x4 + x2 - 8x + 1+ sinx. (i) Evaluate at the point x = : WIN dx (ii) Use forward difference and backward difference approximations of O(Ax) and a central difference approximation of O(Ax2) to estimate their respective approximate first derivative of y at the point x = = using a value of Ax = -. 12 (iii) Estimate the absolute error for the central difference approximation of the derivative obtained in (ii). (iv) Estimate the truncation error for the central difference approximation obtained in (ii)