(Initial Value Problem) Solve for $a$: $ty' - ay = 0$

88 Views Asked by At

$a$ is a constant and the solution passes through the points $(2,1)$ and $(4,4)$

Here are the steps I used to get my answer:

$ty' - ay = 0$

$y' - (a/t)y = 0$

$p(t) = -a/t$, $P(t) = -aln|t|$

$μ(t) = e^{P(t)} = e^{-aln|t|}$

$y'e^{-aln|t|} - (a/t)ye^{-aln|t|} = 0$

$(ye^{-aln|t|})' = 0$

$ye^{-aln|t|} = C$

$y = Ce^{aln|t|}$

Plugging in my two points, I get:

$1 = Ce^{aln|2|}$

$4 = Ce^{aln|4|}$

Dividing these two equations, I get:

$4 = e^{aln(2)}$

$ln(4) = aln(2)$

$a = ln(2)$

But the answer to my book says $a = 2$, and I can't seem to find my mistake.