write equations of the horizontal and the vertical lines tha

中文是
一系列的直线方程
e.g1
x+y =3
2x+6y=0
e.g2
x+y+z =0
x-y+z =5
x+3y-z =3
...

利用消元法求解每个方程组
1.x-y=1 (1)
x+y=3 (2)
解 (2)-1×(1)代替(2),原方程组化为
x-y=1 (1)
2y=2 (2)
解得y=1代入(1)得x-1=1,x=2,故方程组的解为
x=2,y=1.
2.3x-y=26 (1)
-2x-y=-24 (2)
解 (2)-(-2/3)×(1)代替(2),原方程组化为
3x-y=26 (1)
(-5/3)y=-20/3 (2)
解得y=4代入(1)得3x-4=26,x=10,故方程组的解为
x=10,y=4.

　　A simple pendulum consists of a string,cord,or wire that allows a suspended mass to swing back and forth.The categorization of "simple" comes from the fact that all of the mass of the pendulum is concentrated in its "bob" - or suspended mass.
　　The length of the pendulum is measured from the pendulum's point of suspension to the center of mass of its bob.Its amplitude is the string's angular displacement from its vertical or its equilibrium position.If a pendulum is pulled to the right side and released to swing back and forth,its path traces our a sine curve as shown below.
　　The time required for one complete vibration,for example,from one crest to the next crest,is called the pendulum's period and is measured in seconds.
　　The formula to calculate this quantity is
　　where
　　L is the length of the pendulum in meters
　　g is the gravitational field strength,or acceleration due to gravity
　　This quantity at sea level is 9.81 m/sec2 and can be calculated as
　　where
　　G = 6.67 x 10-11 nt m2/kg2
　　M Earth is the mass of the earth (6.02 x 1024 kg)
　　R Earth is the average radius of the earth (6.4 x 106 meters)
　　Notice in the formula that the mass of a simple pendulum's bob does not affect the pendulum's period; it will however affect the tension in the pendulum's string.
　　In this related lesson,you will find a derivation of this formula for the period of a simple pendulum that will help you understand the restrictions on its use.It will also explain to you why a simple pendulum is NOT a true representation of simple harmonic motion,SHM.Take a few moments and use this physlet to investigate how the period of a pendulum is impacted by its length and its initial displacement.
　　The frequency of a pendulum represents the number of vibrations per second.This quantity is measured in hertz (hz) and is the reciprocal of the pendulum's period.
　　Let's practice a few problems with these formulas.
　　What would be the period of a pendulum located at sea level if it is 1.5 meters long?
　　If the pendulum's length were to be shortened to one-fourth its original value,what would be its new period?
　　How many complete vibrations would this shorter pendulum trace out in one minute if it were to be released with a small initial amplitude?
　　At sea level,how long would a pendulum be if it has a frequency of 2 hz?
　　The timing mechanism in a grandfather's clock is based on the principles of a simple pendulum.If your clock is gaining time,should you shorten or lengthen its pendulum?
　　Would a grandfather clock keep time on the moon?
　　A physical pendulum could be illustrated by swinging a meter stick about one end or a baseball bat about one end.The formula to calculate the period of a physical pendulum is
　　where
　　is the pendulum's moment of inertia measured in kg m2
　　m is its mass in kilograms
　　g is the local gravitational field strength or acceleration due to gravity
　　L is the moment arm or perpendicular distance from the pivot point to object's center of mass measured in meters

(a) 3 - x/8 = 5x/2 - 2(x-4)/3 + 5
72-3x=60x-16x+64+120
x=-112/47
(b) 7(x-6) - 6(x+3) = 5 (x-6) - 2(3+2x)
No solution
(c) 三次根号下(5x + 9) = 6
5x+9=216
x=41.4

在平面直角坐标系中有一条曲线,其参数方程是：x=cost,y=sint.问当他的范围是0

这些方程描述了液晶指向矢动力学的情况,它们是根据近晶层的可压缩性连续弹性理论,有限锚定能,定向膜介电属性,实际电路的外部因素等推导而来.

k-x2=x2
x2=k2
Because the length of AB is integer,then the value of x is integer,and so k2 can not be 12.

y=0.5x①
y=1.5x+4②
①×3-②得：3y-y=2y=1.5x-1.5x-4=-4
解得：y=-2
x=-4
制图的话：lz画出两条直线,看看交点坐标即可

以下的式子中,哪个可以用来解出x?如果5x-7=3*x+5
product of明显是乘积嘛

（a）设平面方程为ax+by+cz+d=0
将三个点代入方程得方程组：
5a+4b-8c+d=0
a+6b-3c+d=0
7a-2b+5c+d=0
解之得：
a=-7/46d
b=-31/184d
c=-5/92d
代入平面方程并约去d,得平面方程为：
28x+31y+10c=184
(b) 当t=0时,（x,y,z)=(3;-2;1)
t=-1时,(x;y;z)=(1,-3,4)
所以平面过(1;-2;4),(3;-2;1),(1;-3;4)
同上设平面方程为ax+by+cz+d=0
代入三点得方程组：
a-2b+4c+d=0
3a-2b+c+d=0
a-3b+4c+d=0
解之得：
a=-3/11d
b=0
c=-2/11d
代入平面方程并消去d得平面方程为：
3x+2z-11=0

两边求导
12x+3y+3xy'+4yy'+17y'=0
y'=-(12x+3y)/(3x+4y+17)
则过点(-1,0)的切线斜率为
k=-[12*(-1)+3*0]/[3*(-1)+4*0+17]
=12/14
=6/7
所以切线方程为y=(6/7)(x+1)
即6x-7y+6=0
垂线的斜率为k'=-1/k=-7/6
方程为y=-7/6(x+1)
即7x+6y+7=0

1、a-b=-3（1）
3a-4b=-5 （2）
（1）*3-（2）得
b=-4
a=b-3=-7
2、p+4q=3（3）
5p-8q=1 （4）
（3）*5-（4）得
28q=14
q=0.5
p=3-4q=1
3、y+3=3x（5）
3x-2y=0（6）
（5）代入（6）得
y+3-2y=0
y=3
x=(y+3)/3=2
4、x+y-5=0 （7）
3x-2y-16=0 （8）
（7）*2+（8）
5x-26=0
x=5.2
y=-0.2

(a)dy/(y^(1/2)) = 4dx/x2y^(1/2) = 4ln|x| + cx = 1,y = 1:c = 2√y = 2ln|x| + 1y = (lnx² + 1)²(b)dy/y = 2dx/(x² - 3x +2) = [2/(x - 2) - 2/(x - 1)]dxln|y| = 2ln|x - 2| - 2ln|x - 1|+ cx= 0,...

ones在这里指代 the right equations ,你也可以去比较其他选项 ,语感可以告诉你这个答案才是对的 呵呵
through 和among是不能互换的 through是通过,穿过的意思 而among是在.之中 尤其至在三个或三个以上的人之间 如 ,among them ,among these students . 但不能说 among space!切忌 作文中写这样的句子 太中文思维了!并不是所有有那个中文意思的单词都能应用到相应的中文句子里!

车辆运动在直角坐标系(XOY)中的微分方程式,可以通过将自然坐标系中的力和阻力在X,Y轴上的分量投射在已知角度a来获得.

是整理方程,将x 放在一边的意思.

问题5找到方程,通过所有层面的积分(1,1:1)和(2,0:1),也基于“增大化现实”技术

R equals to R1 times R2 divided by open bracket,R1 plus R2,close bracket.
F equals to half times 2P square root of Rc.
I am Canada born Chinese,trust my answer...this is what I speake at school.lol

x^2+y^3-3*x*y=0
(x^2+y^3-3*x*y)'=0'
2*x+2*y^2*y'-(3*y'*x+3*y)=0
y'=(2*x-3*y)/(3*x-2*y^2)
隐函数求导
注：(y^3)'=y'*y*y+y*y'*y+y*y*y'
y是一个函数,比如f(x).
而x是自变量
(x^3)'=3*x^2
代入x,y即可
法线,据互相垂直的直线斜率k1*k2=-1

应该是：ordinary differential equations(常微分方程) 比 differential equations(微分方程)
常微分方程比微分方程简单,因为微分方程还包括偏微分方程

解决与变量方程
这个网址 自己看：http://translate.google.cn/translate_t?hl=zh-CN&sl=zh-CN&tl=en#en|zh-CN|solving%20equations%20with%20variables%20

在xy坐标系里,参数方程x=cos(t) and y= sin(t),0≤t≤π的曲线长度

我chemistry take了3遍.这个看来很简单.
你好象写错了吧?中间那个-应该是=吧.
如果是的话：
1.2H2+O2=2H2O
2.N2+3H2=2NH3
3.4P+5O2=2P2O5
你知道字母前的数字是大的,字母后的数字是小的吧.just like how they write it on the book.然后既然叫“balance”equation顾名思义就是要把等号左边和右边的balance.就是说左边有几个H右边也应该有几个H,左边有几个O,右边也应该有几个O,2H2的计算方法是2X2=4,所以有4个H.
想当年我也为这种问题烦恼.多做做题就好了,其实可以去问老师.他们很NICE.SO..GOOD LUCK LA~

第一个2(C6H5COOH)+K2SO3→2(C6H5COOK)+SO2↑+H2O
弱酸不拆,可溶盐拆,有2(C6H5COOH)+2（K+）+（SO3）2-→2C6H5COO-+2（K+）+SO2↑+H2O
2(C6H5COOH)+（SO3）2-→2（C6H5COO-）+SO2↑+H2O
第二个
NaHSO4+LiOH=LiNaSO4+H2O
HSO4-有的必须拆,有的可以不拆,不同的地方有不同的要求,一般还是拆掉
关键在于LiOH是否是强碱,说法不一,我个人认为是,那么得(H+)+OH-=H2O

题目是供求的方程分别为S=..D=...
要求供求平衡,就是S=D,得出P=300
当为平衡价格时,需求量是D=-4/3P+500=100

generalized estimating equations
广义估计方程
例句The longitudinal association between migraine and cognitive changes was assessed by generalized estimating equations.
在偏头痛和非偏头痛患者之间的纵向关联由普通估计方程来评估.Objective:Based on the longitudinal data,to probe how to model the generalized estimating equations,and to provide methodological references to the analysis of longitudinal data.
摘要目的：探讨如何利用纵向资料拟合广义估计方程,为纵向资料分析提供方法学参考.