5(х-2)-12х=32 2)2х+3(5-х)=15,5 3)15-4(7+2х)=1

Question

Алгебра: 5(х-2)-12х=32 2)2х+3(5-х)=15,5 3)15-4(7+2х)=1

35глис · Accepted Answer

1)tg(π/4-x)≤√3/3 π/6+πn≤π/4-x π/2+πn π/6-π/4+πn≤-x π/2-π/4+πn -π/24+πn≤-x π/4+πn -π/4+πn x≤π/24+πn x∈(-π/4+πn;π/24+πn] 2)2πn≤x≤π+2πn 3π/4+2πn≤x≤5π/4+2πn x∈[3π/4+2πn;π+2πn} 3)cosxcosy=1/4⇒cos(x-y)+cos(x+y)=1/2 ctgxctgy--3/4⇒1/4:sinxsiny=-3/4⇒sinxsiny=-1/3⇒cos(x-y)-cos(x+y)=-2/3 прибавим и отнимем 2сos(x-y)=-1/6⇒cos(x-y)=-1/12⇒x-y=π-argcos1/12 2cos(x+y)=7/6⇒cos(x+y)=7/12⇒x+y=arccos7/12 прибавим и отнимем 2x=π-arccos1/12+arccos7/12⇒x=π/2-1/2arccos1/12+1/2arccos7/16 2y=π-arccos1/12-arccos7/12⇒x=π/2-1/2arccos1/12-1/2arccos7/16...

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