Mathematica question

• Mathematica
A beginner to Mathematica's question:

I try to make the following integration in mathematica 6 and I get back the same expression with the integration symbol next to it. Why?
Integrate[exp[-k*z]*BesselJ[0, k*a]* BesselJ[1, k*a], {k, 0, Infinity}]

Integrate[Sin[k], {k, 0, 1}] however gives the correct answer.

Not that it matters, the equation comes in one of Jackson's problems and I have seen solutions on the net that seem to make a jump to the solution saying 'using Mathematica...'

A beginner to Mathematica's question:

I try to make the following integration in mathematica 6 and I get back the same expression with the integration symbol next to it. Why?
Integrate[exp[-k*z]*BesselJ[0, k*a]* BesselJ[1, k*a], {k, 0, Infinity}]

Integrate[Sin[k], {k, 0, 1}] however gives the correct answer.

Not that it matters, the equation comes in one of Jackson's problems and I have seen solutions on the net that seem to make a jump to the solution saying 'using Mathematica...'

Try correcting the expression. In particular, the Mathematica command for $e^x$ is

Code:
Exp[x]

and not

Code:
exp[x]

eureka