Question

prove the following identity:

2cosx-2cosy=[(cos2x+cos2y)/(sinx+cosy)]

Answer 1

i got 2cosy-2sinx not 2cosx-2cosy

Answer 2

maybe you can play with this

Answer 3

maybe my teacher messed up the assignment - that must be right. how did you get it? 0_0

Answer 4

i will me watching a movie but it is in the attachment above
ask questions if you have any and i will reply later

Answer 5

thanks :) i'll play with it - i think my teacher must have typo'd. enjoy your movie

Answer 6

I checked all the work - it looks good, and I can find absolutely no way to get to what he wrote. i'll talk to him - thanks for the help!