added grapher file for pythagorean triads
	new file:   PythagoreanTriads.gcx
added D sin functions
	modified:   PythagoreanTriads.gcx
	new file:   PythagoreanTriads.png
	modified:   PythagoreanTriads.gcx
Merge branch 'master' of https://github.com/RandyMcMillan/MAC1147

* 'master' of https://github.com/RandyMcMillan/MAC1147:
  modified:   .gitignore 	new file:   MAC1147Grade.xlsx
  .gitignore
  fixing AudioLectures Commit 	new file:   PythagoreanTriads.gcx 	new file:   PythagoreanTriads.png 	new file:   trig_graph.gif