Exercises for chapter 2

Enhancing MathPlugin

Enhance our MathPlugin with trigonometrical functions (sine, cosine, and tangent).

Actually, it is just about adding the missing directives and using the Math object's functions in it. Open VueMathPlugin.js and add the following:

//VueMathPlugin.js
export default {
  install: function (Vue) {
    Vue.directive('square', function (el, binding) {
      el.innerHTML = Math.pow(binding.value, 2);
    });
    Vue.directive('sqrt', function (el, binding) {
      el.innerHTML = Math.sqrt(binding.value);
    });
    Vue.directive('sin', function (el, binding) {
      el.innerHTML = Math.sin(binding.value);
    });
    Vue.directive('cos', function (el, binding) {
      el.innerHTML = Math.cos(binding.value...