POWER() function returns the result of a number raised to power.
LOG() function returns the logarithm of a number to the base you specify.
You write firstly the number and the power for POWER() function. For LOG() function, you first write the number and the base.
Whereas " =ROW() " function gives the row number of B20, " =ROW(C10) " gives the row number of C10 without regarding where the formula is written.
You also write the cell names in the paranthesis, where the numbers are.