Before working through this chapter, it helps to recall the standard derivatives and differentiation rules you've already met in Class XI. For a power function, dxd(xn)=nxn−1; for an exponential function, dxd(ax)=axloga and, as a special case, dxd(ex)=ex; and for the natural logarithm, dxd(logx)=x1. The derivative of any constant is zero.
Alongside these, four basic rules let you differentiate combinations of functions:
dxd[kf(x)]=kdxdf(x), where k is a real number
dxd[f(x)±g(x)]=dxdf(x)±dxdg(x)
dxd[f(x)g(x)]=f(x)dxdg(x)+g(x)dxdf(x) — the product rule
dxd[g(x)f(x)]=[g(x)]2g(x)dxdf(x)−f(x)dxdg(x) — the quotient rule …