Question

what am i doing wrong?

Answer 1

I got
f(6)=173
f(8)=293
f(10)=445

2(173+293+445)+1892

Answer 2

for the first question

Answer 3

first, those are the right end points. 2nd, I get 1822 not 1892

for the left end points I think it is 2(85+173+293)

Answer 4

thanks for your help!