The Student Room Group
Reply 1
width * 1/2(f(-0.5) + f(0)) + width* 1/2(f(0) + f(0.5))

0.5* 1/2(rt(2-1/8) + rt(2)) + 0.5 * 1/2(rt(2+1/8) + rt(2))

calculator........
1.41
Reply 2
chazzinio
use the trapezium rule with ordinates at x=-0.5, 0 and 0.5 to find an approximate value for


(integration sign!)


0.5 -----
|
|
| root(2+x^3) dx
|
|
-----
-0.5

answer should be 1.41 but i cant get there.

thanks

Let f(x) = root(2+x^3)
then f(0.5) = root(2+0.125) = root(2.125)
...... f(0) = root2
...... f(-0.5) = root(2-0.125) = root(1.875)

Using trapezium rule with h = 0.5

INT f(x) dx is approx
~ 0.5/2(root(2.125) + 2(root2) + root(1.875))
= 1.41 (to 2.d.p)