Решите системы уравнений и подробно распишите решение​


Решите системы уравнений и подробно распишите решение​

alyonasmirnova5 alyonasmirnova5    1   17.01.2021 23:30    0

Ответы
анна2259 анна2259  16.02.2021 23:30

1) \left \{ {{y=0,5x^2} \atop {y-x=1}} \right.

0,5x^2 - x = 1

x=1 + \sqrt{3}

x = 1 - \sqrt{3}

y= 0,5(1+\sqrt{3})^2

y=0,5(1-\sqrt{3})^2

y=2+ \sqrt{3}

y=2-\sqrt{3}

(x_{1\\}, y_{1}) = (1+\sqrt{3}, 2+\sqrt{3})

(x_{2}, y_{2}) = (1-\sqrt{3}, 2-\sqrt{3})

\left \{ {{2+\sqrt{3}= 0,5(1+\sqrt{3}) ^2 } \atop 2+ \sqrt{3} - (1+ \sqrt{3} ) = 1

\left \{ {{2-\sqrt{3}=0,5 (1+\sqrt{3})^2 } \atop {2-\sqrt{3}-(1-\sqrt{3})=1 }} \right.

\left \{ {{3,73205=3,73205} \atop {1=1}} \right.

\left \{ {{0,267949=0,267949} \atop {1=1}} \right.

(x_{1} , y_{1} ) = (1 + \sqrt{3} , 2+ \sqrt{3} )\\

( x_{2} , y_{2} ) = (1- \sqrt{3} , 2-\sqrt{3} )

2) \left \{ {{x+2y=1} \atop {2x+y^2= -1}} \right.

\left \{ {{x=1-2y} \atop {2x+y^2=-1}} \right.

2(1-2y) +y^2 = - 1

y=1\\y=3

x=1-2*1\\x=1-2*3

x=-1\\x=-5

(x_{1} , y_{1} ) = (-1,1) \\( x_{2} , y_{2} = (-5,3)

\left \{ {{-1+2*1=1} \atop {x*(-1)+1^2=-1}} \right.

\left \{ {{-5+2*3=1} \atop {2*(-5)+3^2 = -1}} \right.

\left \{ {{1=1} \atop {-1=-1}} \right.

\left \{ {{1=1} \atop {-1=-1}} \right.

( x_{1} , y_{1} ) = (-1,1)\\( x_{2} , y_{2} ) = (-5,3)

3)  \left \{ {{x^{2} +xy-y^2 = 4} \atop {3x+y=10}} \right.

\left \{ {{x^{2} + xy-y^2=4} \atop {y=9}} \right.

x^2+x*9-9^2=4

x= \frac{-9+\sqrt{421} }{2} \\x= \frac{-9-\sqrt{421} }{2}

( x_{1} , y_{1} ) = ( \frac{-9+\sqrt{421} }{2} , 9 )\\( x_{2} , y_{2} ) = ( \frac{-9-\sqrt{421} }{2} , 9)

\left \{ {{(\frac{-9+\sqrt{421} }{2})^2+\frac{-9+\sqrt{421} }{2}*9-9^2=4) } \atop {1+9=10}} \right.

\left \{ {{( \frac{-9-\sqrt{421} }{2})^2+\frac{-9-\sqrt{421} }{2}*9-9^2=4 } \atop {1+9=10}} \right.

\left \{ {{4=4} \atop {10=10}} \right.

\left \{ {{4=4} \atop {10=10}} \right.

( x_{1} , y_{1} ) = ( \frac{-9+\sqrt{421} }{2} , 9)\\( x_{2} , y_{2} ) = ( \frac{-9-\sqrt{421} }{2} , 9 )

4)  \left \{ {{\frac{1}{x}-\frac{1}{y}=\frac{1}{12} } \atop {2x-y=2}} \right.

\left \{ {{\frac{1}{x}-\frac{1}{y}=\frac{1}{12} } \atop {y=-2+2x}} \right.

\frac{1}{x}-\frac{1}{-2+2x} = \frac{1}{12}

x=3\\x=4

y=-2+2*3\\y=-2+2*4

y=4\\y=6

( x_{1} , y_{1} ) = (3,4)\\( x_{2} , y_{2} ) = (4,6)

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