mkData = (c1, c2, n) => {
let priceScale = d3.scaleLinear().domain([0, n]).range([10, 20]),
price,
quantity,
data = [];
for (let i = 0; i < n; ++i) {
price = priceScale(i);
quantity = c1 / (price - c2);
data.push({ price, quantity, pq: price * quantity, c1, c2 });
}
return data;
}