已知x=(2根号2)+1,则分式:x^3-11x-15分之x^2-2x-9 = 急用,
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已知x=(2根号2)+1,则分式:x^3-11x-15分之x^2-2x-9 = 急用,
已知x=(2根号2)+1,则分式:x^3-11x-15分之x^2-2x-9 = 急用,
已知x=(2根号2)+1,则分式:x^3-11x-15分之x^2-2x-9 = 急用,
x=2根号2+1,所以x^2=9+4根号2,另外(x-1)=2根号2
分式的分子=x^2-2x-9=x^2-2x+1-1-9=(x-1)^2-10=-2
分式的分母=x^3-11x-15=x^3-3x^2+3x-1+3x^2-3x+1-11x-15=(x-1)^3+3x^2-14x-14=(2根号2)^3+3x(9+4根号2)-14x(2根号2+1)-14=-1
所以 分式=2
x=(2根号2)+1
x-1=2根号2
(x^2-2x-9)/( x^3-11x-15) = { (x-1)^2-10 } / {(x^3-1)-11(x-1)-25}
= { (x-1)^2-10 } / {(x-1)^3+x(x-1)-11(x-1)-25}
= { (2根号2)^2-10 } / {(2根号2)^3+(2根号2+1)*2根号2-11(...
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x=(2根号2)+1
x-1=2根号2
(x^2-2x-9)/( x^3-11x-15) = { (x-1)^2-10 } / {(x^3-1)-11(x-1)-25}
= { (x-1)^2-10 } / {(x-1)^3+x(x-1)-11(x-1)-25}
= { (2根号2)^2-10 } / {(2根号2)^3+(2根号2+1)*2根号2-11(2根号2)-25}
= { 8-10 } / {16根号2+8+2根号2-22根号2-25}
= 2 / (17-4根号2)
= 2(17-42)/(289-32)
= 2(17-42)/ 257
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