Add Functionality to the PyCalculator.py program

[subhayu99]

@shalini-kumari2000 I assign you to this issue. Your task is to add Sin, Cos, Tan functionality to the PyCalculator program.

Click here to go to the file

[LogMoss]

Hey! If you need help, I can solve this issue.

[subhayu99]

@erkska Shalini has already done the job. If you wish you can work on something else or add your own issue and then work on that.✌🏻