val xStart = -7.0
val xEnd = 13.0


// generate parabola for (x-3)^2 + 4
val xRange = generateSequence(xStart) { it + .01 }.takeWhile { it < xEnd }.toList()
val yParabola = xRange.map { (it - 3).pow(2) + 4 }

val p = letsPlot { x = xRange; y = yParabola } + ggsize(600, 500)

// how do I create tangent line at x = 2
val yLine = xRange.map { -2*it +  9}



p + geomLine(size =1)