形如 f(z)=x~4+px~2+q 的多项式称为双二次多项式。我们知道,在复数域上 f(x)总可按固定的方法分解为四个一次因式之积,此不赘述。本文打算分别谈谈 f(x)在实数和有理数域上的因式分解问题。在实数域上,当 p~2-4q≥0时,我们可以用 Polynomials of the form f(z)=x~4+px~2+q are called biquadratic polynomials. We know that in the complex field f(x) can always be decomposed into the product of four primary factors in a fixed way, which is not repeated here. This paper intends to talk about the factorization of f(x) on real numbers and rational numbers, respectively. In the real number domain, we can use p~2-4q≥0.