1. ## Trapezoidal rule problem

integral (limits: a = -1 and b = 1) or $5e^-2x^2$ (the Latex max confuse: 5e^-2x^2) using 4 strips.

Length = 2 and width = 0.6

$E = 0.677 + 0.677 = 1.354$

$M = 0.169 + 0.169 = 0.338$

$f(x) dx = 1/2 w (E + 2M)$

= 0.25 (1.354 + 2 * 0.338)

= 0.5075

But the answer is actually 5.87...

2. Originally Posted by zapparage
integral (limits: a = -1 and b = 1) or $5e^-2x^2$ (the Latex max confuse: 5e^-2x^2) using 4 strips.

Length = 2 and width = 0.6

$E = 0.677 + 0.677 = 1.354$

$M = 0.169 + 0.169 = 0.338$

$f(x) dx = 1/2 w (E + 2M)$

= 0.25 (1.354 + 2 * 0.338)

= 0.5075

But the answer is actually 5.87...
You have the width wrong. Two divided by four gives w = 0.5.
$f(x)=5e^{-2x^2}$
Integral = 0.5*w*(f(-1) +2*(f(-.5)+f(0)+f(0.5))+f(1))
Integral = 0.5*0.5*(0.677+2*(3.03+5+3.03)+0.677)

3. Sorry it was a typo. I did actually use 0.5