How do Riemann sums work for estimating area under a curve?

[maccaman]

ive been searching for ages on how to do Reimann sums, and none of it makes any sense to me compared to other forms of integration. My problem is i have to use Riemann Sums to estimate the area under the curve f(x) = x^2 between x=2 and x=12. Any help would be hugely appreciated, Thanks

 

[Damned charming :)]

Section 2 of
http://www.geocities.com/pkving4math2tor6/6_the_intgrl/6_01_03_areas_as_lim_of_riemann_sums.htm

calculates the upper riemann sum of x^2 between 1 and 4. If you also need the lower Riemann sum you just subract the last term and add an appropiate first term.

 

[maccaman]

thanks heaps for the post, really helps me, cheers