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標題:

f.4 a．mathshelp(15 points)

發問:

1)Given x^2 - 6x + 11 ≡ (x + a ) ^ 2 + b, where x is real.a.Find the values of a and b.b.Using (a), or otherwise, write down the range of possible values of 1/x^2 - 6x +112)It is given that (1 + x + ax^2) ^6 =1+ 6x + Ax^2 + Bx^3 + terms involving higher power of x a.Express A... 顯示更多 1)Given x^2 - 6x + 11 ≡ (x + a ) ^ 2 + b, where x is real. a.Find the values of a and b. b.Using (a), or otherwise, write down the range of possible values of 1/x^2 - 6x +11 2)It is given that (1 + x + ax^2) ^6 =1+ 6x + Ax^2 + Bx^3 + terms involving higher power of x a.Express A and B in terms of a. b.If 6, A and B are in arithmetic sequence, find the values of a. 更新: 2(b)∵6,A,B are in A.P. ∴2A=6+B ＜－－－點得出黎嫁．．．？ ∴12a+30=30a+26 ∴a=2/9

最佳解答:

1(a).x^2-6x+11=x^2-6x+9+2 =(x-3)^2+2 ∴a=-3,b=2 1(b).For x^2-6x+11 x^2-6x+11=(x-3)^2+2 ∴x^2-6x+11>=2 for all real value of x ∴1/(x^2-6x+11)
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