Calculus
posted by Tim .
Finding area under a curve
From [1,3]
2x^2 4x +1

is your curve y = 2x^2  4x + 1 ?
Is your region between the curve and the xaxis within your stated domain ?
Did you notice that the parabola has an xintercept within your domain? 
its from 1 to 3 on the x axis including when it crosses underneath, you subtract that (its like negative area)