About 18 dollars. It was pretty simple just had to add them up and I got 17.88 which estimates to 10 dollars but if you wanna be really smart say about 17 dollars and 30 cents.
It is not differentiable at x=1 since the slope of the tangent line as x -> 1 from the right is 1 while the slope of the tangent line as x->1 from the left is -1
The interest due on the first payment is .. I = Prt .. I = 110,000*.055*(1/12) .. I = 504.17
Then the decrease in principal resulting from the first payment is .. 568.00 -504.17 = 63.83 and the new balance is .. $110,000.00 -63.83 = $109,936.17
