Expand math topic with trig updates. (#2309)
Expand math topic with trig updates. (#2309)

* Expand math topic with trig updates.

* Couple of small puncutation catches.

playi/pxt,Microsoft/pxt,switch-education/pxt,switch-education/pxt,playi/pxt,Microsoft/pxt,switchinnovations/pxt,switch-education/pxt,playi/pxt,switch-education/pxt,switchinnovations/pxt,Microsoft/pxt,Microsoft/pxt,switchinnovations/pxt,Microsoft/pxt,playi/pxt,switch-education/pxt,switchinnovations/pxt