Question: I can't search what does the logarithm code look like in C++? What the code of the logarithm function looks like in C++ in the library cmath? Exactly the code. I don't need to figure out how I can get the logarithm. I want to know how this algorithm works.

Answer: 
You are initializing the click listener to many times, when you click on button 1. You have to move it outside, independent of the first click handler... like this:

BTW, you don't need proxies, you can use arrow functions if you need the context inside.

```js
let elt_boxOne = $("#bx_one");
let elt_boxTwo = $("#bx_two");

elt_boxTwo.hide();

elt_boxOne.click(() => {
    elt_boxTwo.show();
});

elt_boxTwo.click(() => {
    console.log("Hello world");
    elt_boxTwo.hide();
});
```

```css
#bx_one {
    width: 200px;
    height: 50px;
    background-color: red;
    text-align: center;
    font-weight: bold;
}
#bx_two {
    width: 200px;
    height: 50px;
    background-color: orange;
    text-align: center;
    font-weight: bold;
}
```

```html
<div id="bx_one">Box one</div>
<div id="bx_two">Box two</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
```
Do not create your "box 2" listener inside of your "box 1" listener. Simply separate the two element's click handlers.

```js
const
  $boxOne = $("#bx-one"),
  $boxTwo = $("#bx-two").hide();

$boxOne.on('click', () => $boxTwo.show());

$boxTwo.on('click', () => {
  console.log("Hello world!");
  $boxTwo.hide();
});
```

```css
.bx {
  width: 200px;
  height: 50px;
  text-align: center;
  font-weight: bold;
}

#bx-one { background-color: red; }
#bx-two { background-color: orange; }
```

```html
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="bx-one" class="bx">Box one</div>
<div id="bx-two" class="bx">Box two</div>
```