ok so im working through a problem,got part way through and realised i couldnt remeber what to do with power rules,if someone could quickly remind me of the rules!(adsbygoogle = window.adsbygoogle || []).push({});

the question is differentiate

ƒ(x) = 1/x^3

Using

if ƒ(x) = x^n then ƒ'(x) = nx^n-1

and the book answer given is

ƒ(x) = 1/x^3 = x^-3

so the derivative is ƒ'(x) = -3x^-4

now i can understand all but one part of this

the part which is how to get from

1/x³ to x^-³

or why

1/xⁿ becomes x-ⁿ

i remember is one of the basic power laws,just cannot remember how or why its so.

could someone remind me please!

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# Basic algebra/Power laws equation

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