thanks, and another question

bluefiberglass (ricebox1/2)
There are two parts in this question.
a) Prove that if a quadratic equation has consective integers as its coefficients, then it has no real roots.
B), Prove or disprove the theorem that if a quadratic equation has three consecutive integers as its coefficients, then it has no real roots.

Well, I did the second part as :
the quadratic equation (n-1)x*x+nx+(n+1)=0, where n>=2.
then b*b-4ac<0,
it is true.

What should I write the first part? How to tell them apart?
Thanks again.


the third question is ' Prove that f(n)=n*n*n-n*n-4 is a composite number. (ie, not a prime number) for all integers n>2.
(#340474@0)
2002-1-19 -05:00

回到话题: a math question thanks!! Suppose triangle ABC has side lengths a, b, c, Prove that if a*a+b*b+c*c=ab+bc+ac, then triangle ABC is an equilateral triangle.

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