证明:设A,B是m*n矩阵,且R(A)=r1,R(B)=r2,则R(A+_B)&=r1+r2_百度知道
证明:设A,B是m*n矩阵,且R(A)=r1,R(B)=r2,则R(A+_B)&=r1+r2
设A,B是m*n矩阵,且R(A)=r1,R(B)=r2,则R(A+_B)&=r1+r2
提问者采纳
A的列+B的列=A+B的列而A的每一列可以写成A的列空间的基的线性组合B的也可以写成B列空间的基的线性组合从而A+B的列就可以写成A与B的极大无关组的线性组合从而A+B的列这一向量组可以被A和B的极大无关组线性表出从而A+B的列秩不会超过A的列秩+B的列秩得证。
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Weight Gain During and After PregnancyWeight Gain During and After PregnancyAbout 50% of women say that their weight has increased during and after pregnancy. So a very common question arises - Is there any relationship between pregnancy and obesity? This article will discuss this question in detail because abnormal weight gain creates problems for both the mother and the fetus.Extensive studies indicate that a weight gain of 8 to 10 kg (17.5 to 22 pounds) during pregnancy is normal. Generally the weight should come down to its normal level soon after the delivery. But in cases of some women, it does not happen that way. Their weight starts increasing during pregnancy and there is no significant weight loss after pregnancy. Many factors could be responsible for such a phenomenon. Sometimes, a pregnant woman is over fed under the false notion of providing double nutrition ? to the mother and to the child. Many a time, a pregnant woman is not allowed to do any physical work. Lack of physical activity and overeating ? these two factors are generally responsible for the abnormal weight gain during pregnancy. Care should be taken to ensure that the weight gain does not exceed the level suggested by her doctor. For this, an expectant mother should be weighed regularly every month during the first six months of her pregnancy and every fortnight thereafter. Care should also be taken to ensure that there is no weight gain beyond 2 kg on an average,CHI Flat Iron, every month. Hazards of excessive weight gain during pregnancy:1. Effect on the expectant mother: Excessive food intake during pregnancy increases the weight which in turn may cause serious consequences. In case of obese women, the incidence of toxemia of pregnancy, allocation of fetus, unbearable pain and post natal bleeding is very high. Obese women generally do not have normal deliveries. Either a forceps delivery or a Cesarean operation is required. Besides this, the mother’s life is generally in danger for a few days following the delivery. Those women who have a family history of diabetes, heart disease or obesity,ghd, need to take extra precautions during their pregnancy.
2. Effects on the fetus: Maternal obesity increases the risk of fetus mortality by about four times. If the mother is obese during pregnancy, the chances of injury to the tender limps of the fetus during the delivery are also enhanced. Dietary advices necessary during pregnancy:Generally a pregnant woman develops health consciousness. She generally accepts all the suggestions and advice regarding health and soon implements them. Right dietary advice tendered to her at this stage may help her to permanently alter the feeding habits of the whole family and thereby prevent the obesity of her children too.Aims of dietary control during pregnancy:1.To check undue weight gain2.To maintain the health of mother and child3.Proper development of fetusDiet plan for pregnant women:1.Take high protein foods.2.Restrict the intake of carbohydrates and fats.3.Increase the intake of raw vegetables and fruits so as to supply vitamins and organic minerals to the body.4.Restrict the use of ghee,ghd, butter, bread, biscuits, cake, sugar, chocolates, sweets, rice, etc.5.There is no harm in consuming the following items freely: grain (ground or powdered by hands), vegetables, fruits, milk, buttermilk,ghd hair, curd, etc.6.Restrict the intake of salt.If a pregnant woman gives up her habit of eating too often, does all the household jobs,ghd IV Styler, goes for a walk in the open air or does any light physical work and prevents obesity, she does not need to worry about any untoward incident during pregnancy of at the time of delivery.Disclaimer: This article is not meant to provide health advice and is for general information only. Always seek the insights of a qualified health professional before embarking on any health program.More articles related to topics：ghds Quitting smoking
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出门在外也不愁一个三阶单位矩阵经过初等转换（比如说交换第2行与第3行的位置)再乘以任意一个三阶矩阵_百度知道
一个三阶单位矩阵经过初等转换（比如说交换第2行与第3行的位置)再乘以任意一个三阶矩阵
最后得到的矩阵是否是将那个所乘的三阶矩阵第2行与第三行位置交换一下。
是的. 左乘一个初等矩阵, 相当于对这个矩阵施行相应的初等行变换右乘一个初等矩阵, 相当于对这个矩阵施行相应的初等列变换一个三阶单位矩阵经过初等转换（比如说交换第2行与第3行的位置) 得到的矩阵 就是一个初等矩阵!满意请采纳 ^-^.