The arctangent value of  0  is 0 
*** TEST #1 PASSED ***
The arctangent value of  .5  is .463648 
*** TEST #2 PASSED ***
The arctangent value of -.5  is-.463648 
*** TEST #3 PASSED ***
The arctangent value of  1  is .785398 
*** TEST #4 PASSED ***
The arctangent value of -1  is-.785398 
*** TEST #5 PASSED ***
*** ALL TESTS PASSED ***
