Y=1/sin²x
y(-10π/3)=1/sin²(-10π/3)=1/sin²(-3π-π/3)=1/sin²(-π-π/3)=1:(√3/2)²=1:3/4=4/3=1 1/3
y(-19π/4)=1/sin²(-5π+π/4)=1:(-√2/2)²=1:1/2=2
А) <span>(х+1)^2-4=0
x^2-2x+1-4=0
x^2 -2x-3=0
D=b^2-4ac=4-4*1*(-3)=4+12=16
x1=-b+кв.кореньD/2a=2+4/2=3
x2=</span>-b-кв.кореньD/2a=2-4/2=-1
<span>б) (х+2)^2-9=0
</span>x^2+4x+4-9=0
x^2+4x-5=0
D=b^2-4ac=16-4*1*(-5)=16+20=36
x1=-b+кв.кореньD/2a=-4+6/2=1
x2=-b-кв.кореньD/2a=-4-6/2=-4-6/2=-10/2=-5
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