Calculate the B field inside and outside a wire

Homework Statement

A long, straight wire of radius a has current density J = J0e−β(α−ρ)uz where β is a
constant and ρ < α. Determine B inside and outside the wire.

Homework Equations

J=I/((pi)a^2)
B=(μIρ)/(2(pi)(a)^2)

The Attempt at a Solution

Here is what I did B=(μρ/2)J0e^(-β(alpha-ρ))

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Is the problem confusing?

Is the problem confusing?

Not at all. First find i by integrating J then find B. di = JdA

So ∫J0e^-β(α-ρ) from 0 to a but what should I integrate with respect too?

J=di/dA maybe?

well since beta is constant and alpha is greater than rho then e^(-beta(alpha-rho)) whould go to 0 if I took the limit from 0 to infinty

hmmm well I guess the problem does not consider time as it uses J0 which I assume stands for the intial value

So my limit I idea is flawed then

Anything else?