Maybe because it's getting late in the evening but I am lost as to how to begin these three problems:

1. Find f(x). f'(x) = e^x - sin(x), f(0) = 1.

2. Find s(t). s''(t) = -1, s'(0) = 3, s(0) = 7.

3. The integral with lower limit 1 and upper limit e, (3/x)dx

Could someone help me get these started? Thanks!