Version 4.0

Finishing implement the rest of csc, sec function and passing all the tests

Version 3.0

Implemented tan & cot function by using the sin & cos, and got tests run for sin & cos successful.
And fix the tests for cot that have incorrect except results cause tests fail

Version 2.0

Implemented sin & cos function using taylor series approximation,
and got tests run for sin & cos successful

Version 1.0

Implemented Test Class

Version 0.0

Update README.md