1
3a²-1/4*ax-4a+5a³x
2
-6a^4b²+8a³b^5
3
5a²b³(3b^4-4a)
4
(x-y)(6ab^5+15a³b²)=3ab²(x-y)(2b³+5a²)
5
27x³y³-9x^4y-3xy³+9x5+9x^4y=27x³y³-3xy³+9x^5
1 рабочий изготовил х деталей второй (х+0,15х)=1,15х деталей.
Вместе изготовили х+1,15х=2,15х=86
х=86:2,15=40
1,5х=46 (или 86-40=46)
2ст-x
x+x+(x+x)+14,2))=76
4x=76-14,2
4x=61,8:4
x=15,45(см)-1 сторона
(15,45+15,45)+14,2=30,9+14,2=45,1
Sin2α=2sinα*cosα⇒sinα*cosα =(sin2α)/2. sin(π -α) =sinα
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9.
cosπ/9*cos2π/9*cosπ/3*cos4π/9 =(1/2)*cosπ/9*cos2π/9*cos4π/9=
(1/2)*sinπ/9*cosπ/9*cos2π/9*cos4π/9 / sinπ/9=
(1/4)*sin2π/9*cos2π/9*cos4π/9 / sinπ/9=(1/8)*sin4π/9*cos4π/9 / sinπ/9=
(1/16)*sin8π/9 / sinπ/9=(1/16)*sin(π-π/9) / sinπ/9=(1/16)*sinπ/9) / sinπ/9 =1/16.
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10. y =sinx/8 -sin(x/8 -π/2) =sinx/8 -sin(-(π/2 - x/8))=sinx/8 +cosx/8 =√2sin(x/8 +π/4).
T =16π.
* * * sin(x+T)/8 +π/4) =sin(x/8+π/4 +T/8) = sin(x/8+π/4).
T/8 =2π⇒T =16π.