Khan/khan-exercises — Issue #15762: Trigonometry challenge - wrong answer?
Author: KhanBugz
Created: 2012-03-08 22:49:04+00:00
State: open
Labels: firefox, wrong-or-unclear, xp

Reporter: mweiss@slb.com

second to last step,
the inversion makes no sense to me

[trigonometry_challenge.html?seed=147&problem=25 (trig_identities_1)](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/trigonometry_challenge.html?seed=147&problem=25&debug)

[Answer timeline](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/trigonometry_challenge.html?seed=147&problem=25&debug&activity=%5B%5B%22incorrect-activity%22%2C%22%5C%22None%20of%20the%20above.%5C%22%22%2C335%5D%2C%5B%22hint-activity%22%2C%220%22%2C3%5D%2C%5B%22hint-activity%22%2C%220%22%2C103%5D%5D)

["None of the above."]

Mozilla/5.0 (Windows NT 5.1; rv:10.0.2) Gecko/20100101 Firefox/10.0.2

MathJax is loaded, ready, queue length: 0