Do you mean the x-coordinates of the boundaries of the strips?
For the length of each individual strip, you need to divide the length of your total restriction into the number of strips. In your case, your total length is 1 unit and you need 5 strips so that's 0.2 units each. This means that you're cutting at 0.2, 0.4, 0.6, 0.8. Using these you can then apply either trapezoidal or Simpson's rules for an approximation of the area under your curve.