解決{l}{x^2+2y^2=8}{y=m(x-2)+sqrt{2}} |Microsoft數學求解器

$$\left. \begin{array} { l } { x ^ { 2 } + 2 y ^ { 2 } = 8 } \\ { y = m ( x - 2 ) + \sqrt { 2 } } \end{array} \right.$$

解 x、y

$$x=\frac{2\left(2m^{2}-\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}\text{, }y=\frac{\sqrt{2}\left(-2m|\frac{\sqrt{2}\left(\sqrt{2}m+1\right)}{2}|-\sqrt{2}m+1\right)}{2m^{2}+1}$$

$$x=\frac{2\left(2m^{2}+\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}\text{, }y=\frac{\sqrt{2}\left(2m|\frac{\sqrt{2}\left(\sqrt{2}m+1\right)}{2}|-\sqrt{2}m+1\right)}{2m^{2}+1}$$

使用代換和二次方程式公式的步驟

考慮第二個方程式。 計算 m 乘上 x-2 時使用乘法分配律。

$$y=mx-2m+\sqrt{2}$$

在另一個方程式 x^{2}+2y^{2}=8 中以 mx-2m+\sqrt{2} 代入 y在方程式。

$$x^{2}+2\left(mx-2m+\sqrt{2}\right)^{2}=8$$

對 mx-2m+\sqrt{2} 平方。

$$x^{2}+2\left(m^{2}x^{2}+2m\left(-2m+\sqrt{2}\right)x+\left(-2m+\sqrt{2}\right)^{2}\right)=8$$

2 乘上 m^{2}x^{2}+2m\left(-2m+\sqrt{2}\right)x+\left(-2m+\sqrt{2}\right)^{2}。

$$x^{2}+2m^{2}x^{2}+4m\left(-2m+\sqrt{2}\right)x+2\left(-2m+\sqrt{2}\right)^{2}=8$$

將 x^{2} 加到 2m^{2}x^{2}。

$$\left(2m^{2}+1\right)x^{2}+4m\left(-2m+\sqrt{2}\right)x+2\left(-2m+\sqrt{2}\right)^{2}=8$$

從方程式兩邊減去 8。

$$\left(2m^{2}+1\right)x^{2}+4m\left(-2m+\sqrt{2}\right)x+2\left(-2m+\sqrt{2}\right)^{2}-8=0$$

此方程式是標準式: ax^{2}+bx+c=0。對二次方程式公式 \frac{-b±\sqrt{b^{2}-4ac}}{2a}，將 1+2m^{2} 代入 a，將 2\times 2m\left(-2m+\sqrt{2}\right) 代入 b，以及將 -4+8m^{2}-8m\sqrt{2} 代入 c。

$$x=\frac{-4m\left(-2m+\sqrt{2}\right)±\sqrt{\left(4m\left(-2m+\sqrt{2}\right)\right)^{2}-4\left(2m^{2}+1\right)\left(8m^{2}-8\sqrt{2}m-4\right)}}{2\left(2m^{2}+1\right)}$$

對 2\times 2m\left(-2m+\sqrt{2}\right) 平方。

$$x=\frac{-4m\left(-2m+\sqrt{2}\right)±\sqrt{16m^{2}\left(-2m+\sqrt{2}\right)^{2}-4\left(2m^{2}+1\right)\left(8m^{2}-8\sqrt{2}m-4\right)}}{2\left(2m^{2}+1\right)}$$

-4 乘上 1+2m^{2}。

$$x=\frac{-4m\left(-2m+\sqrt{2}\right)±\sqrt{16m^{2}\left(-2m+\sqrt{2}\right)^{2}+\left(-8m^{2}-4\right)\left(8m^{2}-8\sqrt{2}m-4\right)}}{2\left(2m^{2}+1\right)}$$

-4-8m^{2} 乘上 -4+8m^{2}-8m\sqrt{2}。

$$x=\frac{-4m\left(-2m+\sqrt{2}\right)±\sqrt{16m^{2}\left(-2m+\sqrt{2}\right)^{2}-64m^{4}+64\sqrt{2}m^{3}+32\sqrt{2}m+16}}{2\left(2m^{2}+1\right)}$$

將 16m^{2}\left(-2m+\sqrt{2}\right)^{2} 加到 16+32m\sqrt{2}-64m^{4}+64m^{3}\sqrt{2}。

$$x=\frac{-4m\left(-2m+\sqrt{2}\right)±\sqrt{32m^{2}+32\sqrt{2}m+16}}{2\left(2m^{2}+1\right)}$$

取 16+32m^{2}+32m\sqrt{2} 的平方根。

$$x=\frac{-4m\left(-2m+\sqrt{2}\right)±4\sqrt{2m^{2}+2\sqrt{2}m+1}}{2\left(2m^{2}+1\right)}$$

2 乘上 1+2m^{2}。

$$x=\frac{-4m\left(-2m+\sqrt{2}\right)±4\sqrt{2m^{2}+2\sqrt{2}m+1}}{4m^{2}+2}$$

現在解出 ± 為正號時的方程式 x=\frac{-4m\left(-2m+\sqrt{2}\right)±4\sqrt{2m^{2}+2\sqrt{2}m+1}}{4m^{2}+2}。 將 -4m\left(-2m+\sqrt{2}\right) 加到 4\sqrt{1+2m^{2}+2m\sqrt{2}}。

$$x=\frac{-4m\left(-2m+\sqrt{2}\right)+4\sqrt{2m^{2}+2\sqrt{2}m+1}}{4m^{2}+2}$$

-4m\left(-2m+\sqrt{2}\right)+4\sqrt{1+2m^{2}+2m\sqrt{2}} 除以 2+4m^{2}。

$$x=\frac{2\left(2m^{2}+\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}$$

現在解出 ± 為負號時的方程式 x=\frac{-4m\left(-2m+\sqrt{2}\right)±4\sqrt{2m^{2}+2\sqrt{2}m+1}}{4m^{2}+2}。 從 -4m\left(-2m+\sqrt{2}\right) 減去 4\sqrt{1+2m^{2}+2m\sqrt{2}}。

$$x=\frac{8m^{2}-4\sqrt{2m^{2}+2\sqrt{2}m+1}-4\sqrt{2}m}{4m^{2}+2}$$

8m^{2}-4m\sqrt{2}-4\sqrt{1+2m^{2}+2m\sqrt{2}} 除以 2+4m^{2}。

$$x=\frac{2\left(2m^{2}-\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}$$

x 有兩種答案: \frac{2\left(2m^{2}-m\sqrt{2}+\sqrt{2m^{2}+1+2m\sqrt{2}}\right)}{1+2m^{2}} 和 \frac{2\left(2m^{2}-m\sqrt{2}-\sqrt{2m^{2}+1+2m\sqrt{2}}\right)}{1+2m^{2}}。在方程式 y=mx-2m+\sqrt{2} 中以 \frac{2\left(2m^{2}-m\sqrt{2}+\sqrt{2m^{2}+1+2m\sqrt{2}}\right)}{1+2m^{2}} 代入 x 以解出滿足這兩個方程式的 y 結果。

$$y=m\times \frac{2\left(2m^{2}+\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}-2m+\sqrt{2}$$

m 乘上 \frac{2\left(2m^{2}-m\sqrt{2}+\sqrt{2m^{2}+1+2m\sqrt{2}}\right)}{1+2m^{2}}。

$$y=\frac{2\left(2m^{2}+\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}m-2m+\sqrt{2}$$

現在在方程式 y=mx-2m+\sqrt{2} 中以 \frac{2\left(2m^{2}-m\sqrt{2}-\sqrt{2m^{2}+1+2m\sqrt{2}}\right)}{1+2m^{2}} 代入 x 取得結果，然後找出滿足這兩個方程式的 y 解。

$$y=m\times \frac{2\left(2m^{2}-\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}-2m+\sqrt{2}$$

m 乘上 \frac{2\left(2m^{2}-m\sqrt{2}-\sqrt{2m^{2}+1+2m\sqrt{2}}\right)}{1+2m^{2}}。

$$y=\frac{2\left(2m^{2}-\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}m-2m+\sqrt{2}$$

現已成功解出系統。

$$y=\frac{2\left(2m^{2}+\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}m-2m+\sqrt{2},x=\frac{2\left(2m^{2}+\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}\text{ or }y=\frac{2\left(2m^{2}-\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}m-2m+\sqrt{2},x=\frac{2\left(2m^{2}-\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}$$

解 x、y (復數求解)

$$\left\{\begin{matrix}x=\frac{2\left(2m^{2}-\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}\text{, }y=\frac{\sqrt{2}\left(-m\sqrt{2\left(\sqrt{2}m+1\right)^{2}}-\sqrt{2}m+1\right)}{2m^{2}+1}\text{; }x=\frac{2\left(2m^{2}+\sqrt{2m^{2}+2\sqrt{2}m+1}-\sqrt{2}m\right)}{2m^{2}+1}\text{, }y=\frac{\sqrt{2}\left(m\sqrt{2\left(\sqrt{2}m+1\right)^{2}}-\sqrt{2}m+1\right)}{2m^{2}+1}\text{, }&m\neq -\frac{\sqrt{2}i}{2}\text{ and }m\neq \frac{\sqrt{2}i}{2}\\x=-\frac{\left(-2m+\sqrt{2}\right)^{2}-4}{2m\left(-2m+\sqrt{2}\right)}\text{, }y=\frac{2m^{2}-2\sqrt{2}m+3}{-2m+\sqrt{2}}\text{, }&m=-\frac{\sqrt{2}i}{2}\text{ or }m=\frac{\sqrt{2}i}{2}\end{matrix}\right.$$