import math._
def f(x: Double): Double = {
    // 3*x*x+x  // or 3*math.pow(3,2)+x
    sin(x)
}
clear
def drawGraph(f:Double=>Double) {
    val (s, e, step) = (-10.0, 10.0, 0.1)
    val (sx, sy) = (10, 100)
    val (tx, ty, t) = (newTurtle, newTurtle, newTurtle)
    runInBackground {
        tx.jumpTo(s * sx, 0); tx.moveTo(e * sx, 0)
    }
    runInBackground {
        ty.jumpTo(0, -1 * sy)
        ty.moveTo(0, sy * (s to e by step).map(f).max)
    }
    runInBackground {
        t.jumpTo(s * sx, f(s) * sy)
        for (x <- s to e by step)
            t.moveTo(x * sx, f(x) * sy)
    }
}
drawGraph(f)