Adding more to Trigonometry

I love Khan Academy and the exercises and videos have really helped me when I was struggling! I was going through the Trigonometry course to supplement another course that I was taking, but the Trigonometry course was lacking in a few things: 

• cofunction identities 
• half angle identities
• power reducing formulas
• product to sum / sum to product

Adding these would be beneficial to the course. Thanks for considering it!