fx-50F "開方" 點禁

For square-root:
There should be a sign like this: √
Example: You want to find √16
Here are the steps:
16 √

For cubic-root:
You need to press Shift first, then press the sign of +/-.
Example: You need to find out 3√1.3653
Here are the process:
1.3653 Shift +/-

I give you the answer as well. That is 1.109369011.

1.3653 SHIFT "/" 3

開方應該是開方的符號，並不是你所寫的。