解方程:2x²+4x+5+1/(x²+2x+2)=4 (急)
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解方程:2x²+4x+5+1/(x²+2x+2)=4 (急)
解方程:2x²+4x+5+1/(x²+2x+2)=4 (急)
解方程:2x²+4x+5+1/(x²+2x+2)=4 (急)
2x²+4x+4+1/(x²+2x+2)=3
2(x²+2x+2)+1/(x²+2x+2)=3
令x²+2x+2=a
则
2a+1/a=3
2a²-3a+1=0
(2a-1)(a-1)=0
a=1/2或a=1
a=1/2的时候
x²+2x+2=1/2
2x²+4x+3=0
判别式
令A=x²+2x+2,则原方程课化为
2A+1+1/A=4
2A²+1=3A
2A²-3A+1=0
(A-1)(2A-1)=0
A=1或A=1/2
x²+2x+2=1或x²+2x+2=1/2
x=-1