open Impact

let redLine(a, b ,m, xlen) = 
    let mutable x = a-xlen
    let mutable xend = a+xlen
    let mutable y = b-xlen*m
    while (x < xend) do
        dot(x,y) red
        x <- x + 0.5
        y <- y + m*0.5
    dot(a,b) black


clear() //comment out this line if you want to see more than one red graph at a time


//let f(x) = sin(x/30.0) * 100.0
//let f(x) = 100.0/((2.0**(-(x-40.0)/4.0)) + 1.0) - 45.0
let f(x) = (-80.0) + (0.5 *x) + 100.*(-(2.**(-(((x-100.)/50.)**2.))) + (2.*(2.**(-(((x-120.)/25.)**2.)))) + (1.5*(2.**(-(((x-60.)/20.)**2.)))))
//let f(x) = 2.0*x-80.0

let fprime(x,h) = (f(x+h) - f(x)) / h
x <- 0.0
while x < 200.0 do
    dot(x,f(x)) pink
    x <- x + 1.0

h <- 25.0
x <- 0.0
while (x < 200.0) do
    dot(x,fprime(x,h)*10.0) red
    m <- fprime(x,h)
    //redLine(x,f(x),m,h*2.0)
    //dot(x,f(x)) black
    x <- x + 1.