1) sin(a+B)-cos(a-B) = sinacosB+ cosasinB - cosacosB - sinasinB =
(sinacosB- sinasinB )+ (cosasinB - cosacosB) = sina(cosB -sinB) +cosa(sinB - cosB) =
= sina(cosB -sinB) - cosa(cosB- sinB ) = (cosB -sinB) ( sina - cosa)
2) cos(a+B)-sin(a-B) = cosacosB - sinasinB- sinacosB+ cosasinB =
= (cosacosB + cosasinB) - (sinasinB + sinacosB) = cosa(cosB + sinB) - sina(sinB + cosB) =
= (cosB + sinB)( cosa -sina)
3) (cosB -sinB) ( sina - cosa)/ (cosB + sinB)( cosa -sina) = (sinB -cosB)/ ( sinB+ cosB )
Вот, вроде правильно
y=x²-4x+4+2
y=x²-4x+6
y'=2x-4
2x-4=0
2x=4
x=2
y=(2-2)²+2
y=2
вершина (2;2)
б) y=(x-4)²-5
y=x²-8x+16-5
y=x²-8x+11
y'=2x-8
2x-8=0
2x=8
x=4
y=(4-4)²-5
y=-5
вершина (4;-5)