Limit step in Laplace transforms

[Jeff12341234]

I'm not sure about the answers to parts of the limit step of the work. Can you explain what the answer to that step should be?

 

[Dick]

I'm not sure about the answers to parts of the limit step of the work. Can you explain what the answer to that step should be?

Use that s>4. If that's so, then both of the exponents are a negative number times b, and so do go to 0 as b->infinity.

 

[Jeff12341234]

thanks