P
phuthuytocnau_00


Rút gọn:
a)[TEX]\frac {sin(\frac{\pi}{4}-\alpha) + cos(\frac{\pi}{4}-\alpha)} {sin(\frac{\pi}{4}-\alpha)-cos(\frac{\pi}{4}-\alpha [/TEX]
b)[TEX]\frac {2sin2\alpha - sin4\alpha} {2sin2\alpha + sin4\alpha}[/TEX]
a)[TEX]\frac {sin(\frac{\pi}{4}-\alpha) + cos(\frac{\pi}{4}-\alpha)} {sin(\frac{\pi}{4}-\alpha)-cos(\frac{\pi}{4}-\alpha [/TEX]
b)[TEX]\frac {2sin2\alpha - sin4\alpha} {2sin2\alpha + sin4\alpha}[/TEX]