Okay i've had a crack at the first one which is the maximum input for the log of n such that the result is <= 1 second.

I started with finding the log of a value that will equal 1.0.

Then i look to find out what value n i can have so that it equals 10.

Each single value of

I need to get

so i do the following:

The log of this is

Thus the greatest value i can have for n when the run time is the log of n and must not be greater than is

is that right?