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歡迎您訪問數學考題練習:關于方程x3+2x2+3x-1=0根的情況判斷!

數學考題練習:關于方程x3+2x2+3x-1=0根的情況判斷

更新時間:2024-01-12 16:25:46作者:貝語網校

關于方程x3+2x2+3x-1=0根的情況判斷正確的是

A.有一個正實數根

B.有兩個不同的正實數根

C.有一個負實數根

D.有三個不同的實數根

試題答案

A

試題解析

本題的解可看作求函數y=x2+2x+3=(x+1) 2+2與y=兩函數的交點的個數,結合圖象得出答案即可.

解答:解:方程x3+2x2+3x-1=0移項得出:

x3+2x2+3x=1,

兩邊同除以x可以變形為:

x2+2x+3=,

可以得出此方程的解可以看做是:y=x2+2x+3=(x+1) 2+2與y=.兩函數的交點的橫坐標,

幾何圖象可以得出:兩函數只有一個交點,且交點在第1象限,

∴關于方程x3+2x2+3x-1=0根的情況有一個正實數根.

故選:A.

點評:此題主要考查了高次方程的解法,通過數形結合,將方程問題轉化為函數交點問題.由圖象可直接得出答案是解題關鍵.

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