By far the most popular and well-stocked category of used instruments is our selection of guitars, where we've got a huge variety of all the big names. Used Gibson Les Paul, pre-owned Fender Telecaster and secondhand Stratocaster guitars are commonly found within these pages, waiting for their new homes with players and collectors.
22/7 is a pretty decent choice for teaching 11-year-olds about fractions that are close to pi. 355/113 would be better, if you think they can remember numbers that big. And approxRational is fun. Exercise for the interested reader: implement an inverse to approxRational.
So since the interval we're looking at is y = sin x, x = -pi/2. . pi/2: At-pi/2, sin x is -1 (since 3pi/2 - 2pi = -pi/2) and at pi/2, sin x = 1. At 0, sin x = 0. So start from (-pi/2, -1), draw the right half of a concave-up curve up to (0,0), then the left half of a concave-down curve up to (pi/2, 1).o since the interval we're looking at is y = sin x, x = -pi/2. . pi/2: At-pi/2, sin x is -1 (since 3pi/2 - 2pi = -pi/2) and at pi/2, sin x = 1. At 0, sin x = 0. So start from (-pi/2, -1), draw the right half of a concave-up curve up to (0,0), then the left half of a concave-down curve up to (pi/2, 1).