let y2

//0-200

let h=200

let width = 30

let res = 1

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(220);

  for(let x = -200; x<=200; x+=(1/res)){

    //problem here

    y = cos(x*(1/width))*h

    y2 = cos((x-1)*(1/width))*h

    point(map(x,-200,200,0,400),y+200);

    line(map(x,-200,200,0,400),y+200,map(x-1,-200,200,0,400),(y)+200)

    if (map(x,-200,200,0,400)==mouseX)

    ellipse(mouseX,y+200,20)

  }

    if (map(x,-200,200,0,400)==mouseX){

    ellipse(mouseX,y+200,20)

  }

}