How do you write an equation in the form f(x) = kx^n for the direct variation functions given f(2) = 8 and n = 4?

1 Answer
Alan P.
Jun 15, 2016

f(x)=kx^n is not a direct variation function

Explanation:

If f(x) were a direct variation function replacing x with a multiple of x would result in the value of f(x) being multiplied by that same multiple.
To be a direct variation f(a*x)=a*f(x)

However,
if the intended question was simply to fin the value of k
given
color(white)("XXX")f(x)=kx^n
and
color(white)("XXX")f(2)=8 when n=4
then
color(white)("XXX")f(2)=k*(2^4)=k*16=8
rArr k=1/2

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