Hey guys, having a blank moment
Could some one just give me an answer to the the derivative of 4/x^-2, the x to the power -2 has thrown me a bit , longer time since i did this i know it basic stuff , having one of those days
The hard way, using the "quotient rule": (f/g)'= (f'g- fg')/g^2 with f= 4, a constant so f'= 0, and $\displaystyle g= x^{-2}$ so $\displaystyle g'= -2x^{-3}$. $\displaystyle (4/x^2)'= [(0)(x^{-2})- (4)(-2x^{-3}]/x^{-4}= 8x^{-3}/x^{-4}= 8x^{-3-(-4)}= 8x$
Gosh, wasn't that fun!