(sina+2cosa)/(5cosa-sina)
=(tana+2)/(5-tana)
=(1/3+2)(5-1/3)
=7/14
=1/2
a²cos(2π)-b²sin(3π/2)+abcos(π)-absin(π/2)
=a²+b²-ab-ab
=(a-b)²
(sina+2cosa)/(5cosa-sina)
=(tana+2)/(5-tana)
=(1/3+2)(5-1/3)
=7/14
=1/2
a²cos(2π)-b²sin(3π/2)+abcos(π)-absin(π/2)
=a²+b²-ab-ab
=(a-b)²