im guessing n=4 means using 4 rectangles

so you would basically break the interval 1,3 into 4 equal pieces
then evaluate f(x) at those places
then calculate the area of each rectangle they create
add them together and there you go

kind of hard to explain without drawing a pic though

for left endpoint
x from 1 to 3 means we have a distance of 2
break that into 4 pieces and we get halfs
so our first rectangle goes from x=1 to 1.5 and its height is f(1)
gives us an area of f(1) * .5 = 5 *.5=2.5

second piece is from x=1.5 to 2, height is f(1.5)
calculate area of this one

then do the other 2 more rectangles, add up all the areas

then for the right endpoints use the first rectangle is from x=1 to 1.5 and height is f(1.5) since its the right side of the rectangle that we care about for height
for midpoint do f(1.25)

does that make sense?

 

Ship makes my brain hurt. I used to be pretty damn good at math.....7 years ago :rofl:.

 

foil = first outside, inside last.

works everytime.

 

Yeah, My professor is a good teacher, but doesn't explain well...You putting it like that really helps

 

good, i havent done this stuff since 2001, so im a bit rusty, but its really not very difficult when you know whats really happening and not just staring blankly at some definition written in a foreign language

just use lots of paper and draw lots of pictures, the more you understand how it works, the easier time you will have further down the road as well

 

Im still stuck

f(x) = 2x +5 from x=2 to x=4

Ive found the midpoint..but i don't know how to find the left and right endpoints

 

never mind i figured it out

 

whack.

 

Man I get it one second then I apply it to another problem and I'm off by .5 from the answer in the back of the book...I wanna make the Deans List but if I gotta put myself through all this stress im bout to say fuck it

 

so where are you getting stuck at?

for the second problem what was n?

have you drawn up a graph and looked at what happens when you use the different points?