二次方程

The equation of conservation of momentum is changed into a quadratic equation of a certain physical quantity.

将动量守恒方程变成一个物理变量的二次方程。

The diversity and evenness are low when the MQCIs are less than 15% and greater than 45%, and reach to high when MQCI in the middle of 15% and 45%. The relationship between MQCI and richness index can be best presented by a cubic equation, and no apparent trend can be found when MQCI is greater than 20%.

多样性和均匀性指数与草甸质量盖度指数之间关系的可以分别用二次方程式进行描述，当高寒草甸的草地质量指数在15%以下时，多样性和均匀性指数均较低，介于15%～45%之间时两者都很高，大于45%后，有下降的趋势；物种丰富度与草甸质量盖度指数之间的关系可用三次方程式进行描述。

The linear function applicable scope is broad, when the reservoir turnover water volume and the time, the student leaves the staircase mouth population and the time and the time and the motion communication speech spends the comparison and so on the relational question has the important application;The study linear function, may deepen in the life the linear question understanding and the understanding, is helpful in solves some simple function problem; The linear function some problem solving method has the universality in mathematics, the linear function related theory may use for to solve some other mathematics problem, For instance the dual linear equation group, a Yuan inequality, a Yuan quadratic equation most value question and some complex mathematics question, the light is studies the linear function the theory is insufficient, the key is can utilize actual the linear function goes is our final goal.

一次函数的适用范围广，在蓄水池的进出水量与时间、学生出楼梯口人数与时间与时间和移动通讯的话费比较等的关系问题时均有重要的应用；学习一次函数，可以加深生活中线性问题的认识与理解，有助于解决一些简单的函数问题；一次函数的一些解题方法在数学中具有普遍性，一次函数的有关理论可以用来解决一些其它的数学问题，比如二元一次方程组、一元一次不等式、一元二次方程的最值问题及一些复杂的数学问题，光是学习一次函数的理论是不够的，关键是能把一次函数运用到实际中去才是我们最终的目的。

As mentioned earlier, the linear form of a consistent error and the error curve in line with the quadratic equation of the curve, with a predictable size and shape.

如前所述，线性误差具有一致的形式，且误差曲线符合二次方程的曲线，具有可预测的大小和形状。

The growth dynamics of leaf length on stem and tiller could be described with a logistic model, leaf width with conic equation, and leaf shape with exponential function and quadratic equation. The effects of nitrogen and water conditions on leaf growth were quantified by the effective values of leaf nitrogen concentration and water content.

模型采用Logistic方程描述了水稻主茎及分蘖叶片随生长度日的动态伸长过程；利用二次曲线描述了叶宽随GDD的动态变化过程；分别用幂函数和一元二次方程描述了叶形的动态变化过程；另外，以叶片氮素和水分因子分别描述了不同水氮水平对叶片形态建成过程的定量影响。

However, taking into account the 16th and 17th centuries when European mathematicians still held the view that negative is "ridiculous number", Fibonacci's awareness of the negative undoubtedly is of great significance.4、Fibonacci's understanding of the irrational depends on the geometry, and the arithmetic of Fibonacci for square root was the tendency of algorithm.

虽他忽视二次方程之负数解，但考虑到16和17世纪，欧洲数学家仍认为负数是"荒谬的数"，斐波那契对负数的认识无疑具有重要的意义。4、斐波那契对无理数的认识有赖于几何图形，"开方法"趋于算法化。

In the beginning of quadratic equations such as, x2-2=0,forced upon us the irrational number, and led to the study of methods of operating with radicals, and to the solution of radical equations.

而二次方程，例如x2-2=0的出现，让我们不得不接触无理数，同时也带来了对于求根方法，以及根方程的研究。

The study wanted to make clear the index of freeze injury to Lichi. Low temperature data of Fujian province recent years and now, information about freeze injury of lichi in survey and literature were gathered, refering to photo and corresponding low temperature data about five county in winter in 1999 that provided by guangxi research institute of meteorological disaster mitigation; by statistic methods dealing with above information gave the result on the extreme low temperature data gathering by thermometer screen and the freeze injury grade of lichi; correlation analysis on data of freeze injury and the extreme low temperature indicated that the temperature of no freeze injury and slight freeze injury and moderate freeze injury and serious freeze injury and most serious freeze injury is respectively -0.3℃ and -1.9℃ and -3.1℃ and -3.8℃ and -4.1℃; Difference of teperature between every freeze injury grade of lichi turned to disappear when grade increased.

为了弄清给荔枝树造成损害程度低温指标，收集了福建省近几年冬季考察的低温资料、荔枝树低温冻害调查资料和有关参考文献中记载的荔枝树冻害资料、同期的低温资料，参考广西壮族自治区气象减灾研究所1999—2000冬季5个县荔枝树冻害的照片资料和相对应的低温资料；经统计处理整理成同时同地荔枝树的冻害级别与百叶箱中的最低气温资料；据荔枝树的冻害资料和最低气温资料进行相关统计分析，经相关分析表明：它们可以用一元二次方程进行拟合；荔枝树的无冻害、轻冻害、中冻害、重冻害、严重冻害的最低气温分别为-0.3℃、-1.9℃、-3.1℃、-3.8℃、-4.1℃；荔枝树各个冻害级别之间温差随着冻害级别的提高而缩小。

Why should anyone try to understand quadratic equations and the principles that lie behind solving them?

hellip；为什么会有人试着去理解二次方程和解答过程背后的原理呢？

The manipulation of sugar can divide the curve of pink wine alcohol fermentation density with the changes of time into two parts when the sugar content of raw material-grape is lower than 12%. The regression analysis results showed that quadrative equation and logarithmic equation can be used to describe changes of density with changes of time before and after replenishing sugar respectively.

当葡萄原料含糖量低于12%酒度要求时，加糖操作可将桃红葡萄酒酒精发酵密度随时间变化的曲线分为2段，用回归分析法分析结果表明，加糖前密度随时间的变化规律可用二次方程描述，加糖后密度随时间的变化规律可用对数方程描述。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。