The function f(x) = ax^r satisfies f(2) = 1 and f(32) = 4. Find r.
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f(x) = ax^r
f(2) = 1
a(2)^r = 1 Divide both sides by 2^r .
a = 1 / ( 2^r)
f(32) = 4
a(32)^r = 4 Divide both sides by 32^r .
a = 4 / ( 32^r)
Set these two values of a equal to each other.
1 / ( 2^r) = 4 / (32^r) Cross multiply.
32^r = 4 * 2^r And we can write 32 and 4 as powers of 2 .
(2^5)^r = 2^2 * 2^r
2^(5r) = 2^(2 + r)
5r = 2 + r
4r = 2
r = 1/2