“渐近线”的英语？

双曲线逐渐接近它的渐近线但不相交.A hyperbola approaches but does not meet its asymptote.讨论一类具有渐近线性项的奇异边值问题.This paper deals with a kind of singular boundary value problems with asymptotically linear term.所以渐近线也可能是一条曲线.不过方便起见我们都讨论渐近“线”.A...