How to use the log chart to see when it's time to sell

[lucacrebbe]

Hello, I was talking with a friend and we ended up talking about how to use the log chart to identify the sell opportunities, he said to me:
When you see the price increasing directly upwards on a log chart, it’s time to sell. when it goes from 0 degrees (flat) up and up and up until it’s forming a 90 degree angle straight up. That’s how you know it’s time to sell.
Why is the log chart so so effective to identify the right time to sell? In this example he speaks of a flat situation at 0 degrees and then a vertical explosion. Why is the chart log more effective?

 

[Enivid]

First and foremost, measuring absolute angles on charts is completely meaningless because the angle depends on a zoom level. So, you can change the angel just by zooming in and out of the chart.

As for the power of the log charts, there is nothing too special about them. If the price is growing rapidly on a log chart, it just means that it grows exponentially, which is usually considered unsustainable, therefore traders may assume that the current price is a bubble. And bubble normally burst sooner or later.