I need to prove the following rules on cardinals:

Let κ, μ, ν be cardinal numbers. Prove:

1. κ^(μ + ν) = κ^μ·κ^ν.--

2. κ^μ·ν = (κ^μ)^ν.

How do I start proving such thing? It looks so obvious, but I'm sure there has to be a formal way to prove it.

Please help me!

Thank you