Question

hey all, need help with this
evaluate integral from -2 to 1 |2x+1|dx

since x>0 from -2 to -1/2 I do -(2x+1)dx| but when I integrate it becomes -(x^2+x) which is then negative from -2 to -1/2

Answer 1

sorry, meant to say x<0 from -2 to -1/2

Answer 2

i wouldn't integrate at all. i would use geometry
draw the function and you will get two triangles

Answer 3

or you can break up the integral in to two parts,
\[\int_{-2}^{-\frac{1}{2}}(-2x-1)dx+\int_{-\frac{1}{2}}^12x+1dx\]

Answer 4

still i think geometry would be easier. take a look at the picture. two triangles, figure one half base times height

Answer 5

http://www.wolframalpha.com/input/?i= |2x%2B1|+x+%3D-2+to+1

Answer 6

yea @satelites got the idea