how to find growth rate

Question

How to find growth rate of below expression
a) $(2/3)^n + (\sum_{i=1}^n) \sin^2n +n^2 +\ln((\sum_{i=1}^n) nCi)$
b)$ nC2 + \sum_{i=1}^n \log n + n^2 \sin n$

I don't understand how to get the growth rate of the above expressions