# Using Trapezoid Rule to approximate $\int^{0}_{-2}\frac{1}{4+x^2}dx$

I need to use the trapezoid rule to approximate the following integral: $$\int^{0}_{-2}\frac{1}{4+x^2}dx$$ for a given step $n=5$.

I'm not exactly sure how to do a problem like this.

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What's the formula you're using for the trapezoidal rule, first of all? –  Ｊ. Ｍ. Jul 30 '12 at 10:58
I'm not really sure actually. en.wikipedia.org/wiki/Trapezoidal_rule –  user69 Jul 30 '12 at 11:02
First things first: how would you divide the interval $[-2,0]$ into four sub-intervals? (If you have four sub-intervals, you have five points; think of the number of fingers in a hand, and the number of gaps in between the fingers.) –  Ｊ. Ｍ. Jul 30 '12 at 11:18
Still not that. Try an increment of $\frac12$. –  Ｊ. Ｍ. Jul 30 '12 at 11:50
$(-2,-3/2,-1,-1/2,0)$. Five points, four panels. –  Ｊ. Ｍ. Jul 30 '12 at 15:00