JohnCU
Banned
Solve.
sin2xsinx - cos2xcosx = -cosx
Using double angle identities...
(2sinxcosx)sinx - (1-2sin^2x)cosx = -cosx
2sin^2xcosx - (cosx - 2sin^2xcosx) = -cosx
2sin^2xcosx - cosx + 2sin^2xcosx = -cosx
Add the cosx to the other side so they cancel...
2sin^2xcosx + 2sin^2xcosx = 4sin^2xcosx
Is this right? This was a quiz question and was marked wrong and I can't figure out what I'm doing wrong.
sin2xsinx - cos2xcosx = -cosx
Using double angle identities...
(2sinxcosx)sinx - (1-2sin^2x)cosx = -cosx
2sin^2xcosx - (cosx - 2sin^2xcosx) = -cosx
2sin^2xcosx - cosx + 2sin^2xcosx = -cosx
Add the cosx to the other side so they cancel...
2sin^2xcosx + 2sin^2xcosx = 4sin^2xcosx
Is this right? This was a quiz question and was marked wrong and I can't figure out what I'm doing wrong.
