首先，我们需要知道未知量是什么。
现在我有了三个方程序和三个未知量。
如何使一个方法以未知量的值？
在模拟计算机中，微分方程的未知量被用电信号来模拟。
In an analog computer, the unknowns in a differential equation are modeled with electrical signals.
方程与算数的等式不同在于它含有可以参加运算的未知量。
Equation is different from arithmetic identity in that it contains unknown quantity which can join operations.
未知量是一个函数，这个方程，将把函数的偏导数联系起来。
So the unknown is a function, and the equation will relate the partial derivatives of that function to each other.
这一方程描述了扩散过程中扩散系数依赖于未知量及其自身梯度。
This equation describes the diffusion coefficient depends on a quantity and its gradient in a diffusion procedure.
方程又称为条件等式，因为其中的未知量通常只允许取某些特定的值。
Equipment is called an equation of condition in that it is true only for certain values of unknown quantities in it.
导出以截面横向位移和节点纵向位移为未知量的有限元法的基本方程。
Taking the lateral displacement of the cross section and the longitudinal displacement of nodes as the basic variables the finite element analysis of thin-walled member structures is formulated.
解方程时要进行一系列移项和同解变形，最后求出它的根，即未知量的值。
To solve the equation means to move and change the terms about without making the equation untrue, until the root of the equation is obtained, which is the value of unknown term.
在建立优化目标函数过程中采用座标形式为未知量，从而使计算公式更为简单。
For establishing the optimal target function we use the coordinate values as the unknown variables and thus the calculating formulas are further simplified.
提出的方法是以结构的预应力分布为未知量，而结构的几何外形由设计者给定。
The prestress distribution in the reference configuration which is explicitly defined by the designer can be effectively found by using the method of this paper.
采用物质坐标，用水平位移作为基本未知量，成为固体力学的非线性大位移问题。
Under the physical coordinate, the horizontal displacement is taken as an unknown quantity, and a nonlinear problem with big displacement of solid mechanics is introduced.
在这种方法中，取支座断面处的弯矩及挠度为未知量，故可称为混合式定点比法。
The bending moments and deflections are taken as unknown variables in this method, and then may be called the method of mixed type of focal coefficients.
由流动的连续性引进了流函数，使流体动力学基本方程的未知量的个数减少一个；
Because of the continuity of the flow, the stream function is introduced and it makes that the numbers of the fluid dynamical basic equation is cut off one.
以裂纹面上的位错函数为未知量将圆柱型界面裂纹问题化成一组奇异积分方程的求解问题。
The problem of a cylindrical interface crack is reduced to a system of singular integral equations with the aid of two unknown dislocation functions at the interface crack surface.
该方法既采用了有限元法处理离散结构的便利，又通过力学途径来减少所需求解的未知量。
The method not only possesses the FEM advantages for discrete structures, but also reduces the unknowns in structural analysis.
首先，采用间接制定正规化边界积分方程的奇异积分处理，可以计算出准确的边界未知量。
To begin with, a regularized boundary integral equation with indirect formulation is adopted to deal with the singular integrals and the boundary unknown quantities can be calculated accurately.
有限条法应用于高层建筑结构时，作为位移未知量的不是楼层处的位移值，而是位移曲线的幅值。
When the finite-strip method is used for the analysis of tall building structures, the unknown quantities are not the values of displacement at the floor level but the parameters of displacement.
在使用有限元法求解波动方程偏移过程中，由于未知量数目巨大，需要花费大量的计算机存储空间和计算时间。
In wave equation migration using finite element method, a great deal of computer's internal storage and computer time are used because of too many unknowns involved.
在半参数回归模型中采用最小二乘估计方法结合局部多项式方法来估计未知量，在一定条件下得到了估计量的相合性。
And estimated the unknown quantity using the methods of least square estimation and local polynomial estimation, obtained the consistency of estimation under certain condition.
但是在处理高频问题和具有精密结构的缝隙时，对目标剖分过密会导致稠密的阻抗矩阵，未知量增加，影响计算的效率。
But for high frequency problem and complex structure, too dense grid of object will lead to dense impedance matrix and many unknown variables, so the computational efficiency will be very low.
以轨道半径和轨道倾角为未知量依据星下点轨迹要求条件构建了非线性方程组，但直接求解过于复杂，采取迭代的方法解决。
Non-linear equations are(constructed) with the restriction of the satellite ground trace to resolve the unknown semi-axis and inclination, but it's too complicated to be resolved directly.
计算结果表明，QR法未知量数目少，避免了有限元、有限条法等传统方法的不足，且与有限元、有限条法分析结果基本一致。
Results show that QR-method have fewer unknown quantities, avoids the shortcomings of traditional method such as finite elements and finite strip method and the results are consistent.
以位移为未知量，根据平衡条件建立了竖向荷载作用下端部固定的空腹桁架节点转角和节间侧移迭代计算公式与固端弯矩的计算方法。
Iterative formulas of nodal rotational Angle and lateral deflection of truss panel and fixed-moment in end-fixing Vierendeel truss subjected to vertical loads are presented in this paper.
以位移为未知量，根据平衡条件建立了竖向荷载作用下端部固定的空腹桁架节点转角和节间侧移迭代计算公式与固端弯矩的计算方法。
Iterative formulas of nodal rotational Angle and lateral deflection of truss panel and fixed-moment in end-fixing Vierendeel truss subjected to vertical loads are presented in this paper.
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