《二元一次不等式表示的平面区域教学ppt课件.ppt》由会员分享，可在线阅读，更多相关《二元一次不等式表示的平面区域教学ppt课件.ppt（65页珍藏版）》请在taowenge.com淘文阁网|工程机械CAD图纸|机械工程制图|CAD装配图下载|SolidWorks_CaTia_CAD_UG_PROE_设计图分享下载上搜索。
1、问题问题1：下列方程的几何意义是什么？：下列方程的几何意义是什么？x+y1=0方方程程的的解解集集在在平平面面直直角角坐坐标标系系中中表表示示一一条条直直线线l l。这这条条直直线线由由无无数数多多个个点点组组成成，其其中点的坐标中点的坐标(x,y)是直线方程是直线方程x+y1=0的解。的解。问问题题2：二二元元一一次次不不等等式式的的解解集集(x,y)|x+y10的几何意义是什么呢？的几何意义是什么呢？()()()x二元一次不等式表示二元一次不等式表示的的平面区域平面区域问题：问题：在平面直角坐标系中画出直线在平面直角坐标系中画出直线x=2.直线直线x=2把整个平面分成几个区域？把整个平面分
2、成几个区域？你能画出下列式子所表示的区域吗？你能画出下列式子所表示的区域吗？在平面直角坐标系中，所有的点被直线在平面直角坐标系中，所有的点被直线x+y-1=0 x+y-1=0分为几类：分为几类：3)3)在直线在直线x+y-1=0 x+y-1=0左下方的平面区域内。左下方的平面区域内。11x+y-1=0()()()x2)在直线在直线x+y-1=0右上方的平面区域内；右上方的平面区域内；直线直线l可以看作是以二元一次方程可以看作是以二元一次方程x+y-1=0的解为坐标的点的集合的解为坐标的点的集合x,y）x+y-1=01)在直线在直线x+y-1=0上上;x+y-1=0平面上任意一点平面上任意一点P
3、 P（x,yx,y），代入），代入x+y-1x+y-1后得到的值后得到的值会有几种情况：会有几种情况：yo点点P（x，y）在直线的哪一区域）在直线的哪一区域内内x+y-1的值大于的值大于0；等于；等于0；小于；小于0?能否在直线外找一点能否在直线外找一点P（x,y）,使得使得x+y-1=0？大于大于0；等于；等于0；小于；小于0如何证明你的判断？如何证明你的判断？思路一思路一：在直线右上方任取一点在直线右上方任取一点(x,y)，过此点作一平行过此点作一平行x轴的直线轴的直线x+y-1=0 xyP0(x0,y0)(x,y)思路二思路二：在直线右上方任取一点在直线右上方任取一点(x,y)，过此点作
4、一平行过此点作一平行y轴的直线轴的直线x+y-1=0 xyP0(x0,y0)(x,y)Xx0,y=y0 x+yx0+y0 x+y-1x0+y0-1=0X=x0,yy0 x+yx0+y0 x+y-1x0+y0-1=0结论：结论：一般地，二元一次不等式一般地，二元一次不等式Ax+By+C0在平面直角坐标系中表示直线在平面直角坐标系中表示直线Ax+By+C0某某一侧所有点组成的平面区域。一侧所有点组成的平面区域。我们把直线画成我们把直线画成虚线以表示区域不包含边界直线。虚线以表示区域不包含边界直线。（同侧同号）（同侧同号）你有什么发现？你有什么发现？能不能猜想出能不能猜想出ykx+b表示的是直线表示
5、的是直线y=kx+b的的 哪部分区域？同样，哪部分区域？同样，ykx+b表示直线表示直线上方上方的平面区域的平面区域 y 0 0时时 Ax+By+CAx+By+C 0 0表示直线表示直线上方上方区域区域 Ax+By+CAx+By+C 0 0表示直线表示直线下方下方区域区域（注：由斜截式转化为一般式进行研究探讨或由一般式注：由斜截式转化为一般式进行研究探讨或由一般式化归为斜截式进行研究探讨，并作比较化归为斜截式进行研究探讨，并作比较）强调：强调：若若B0）例题例题2:根据下列各图中的平面区域用不等式表示根据下列各图中的平面区域用不等式表示出来（图包含出来（图包含y轴）轴）6x+5y=22y=x-
6、1提出：提出：采用采用“选点法选点法”来确定二元一次不等式所表来确定二元一次不等式所表示的平面区域示的平面区域强调强调：若直线不过原点，通常选（若直线不过原点，通常选（0，0）点点;若直线过原点，通常选（若直线过原点，通常选（1，0）、（）、（-1，0）、）、（0，1）、）、(0,-1)等特殊点代入检验并判断。等特殊点代入检验并判断。_1。二元一次不等式表示相应直线的某一侧区域口诀：上大下小斜截式口诀：上大下小斜截式 上正下负一般式上正下负一般式 （B0B0）小结2。画二元一次不等式表示的平面区域的方法：可根据二元一次不等式与B的关系来确定 Ax+By+C0与B的关系为:B0时表示直线上方 区
7、域,B0时表示直线下方区域。Ax+By+C0时表示直线下方区域,B0时 表示直线上方区域初一英语第二学期同步串讲初一英语第二学期同步串讲 第七讲第七讲 Do you have an eraser?Do you have a soccer ball?soccer basketballbadmintonbaseballball gamestennis(racket)volleyballgolfPing pong(ball)table tennis Do you have an American football/rugby?Yes,I do./No,I dont.Golf clubDo you h
8、ave a golf ball?Yes,I do./No,I dont.Group workNames Do you have a?Balls you haveLucyYes,I do.basketballWhat balls do you have?I have.l1.你有一个排球吗？你有一个排球吗？是的，我有。是的，我有。l2.你有表兄妹吗你有表兄妹吗?不不,我没有。我没有。l3.她有网球拍吗？她有网球拍吗？是的，她有。是的，她有。l7.咱们去踢球吧。咱们去踢球吧。Do you have a volleyball?Yes,I do.Do you have any cousins?No,I
9、dont.Does she have a tennis racket?Yes,she does.Lets play soccer.l4.他有英英字典吗？他有英英字典吗？不，他没有。他有一本英不，他没有。他有一本英汉字典。汉字典。l5.他们有笔记本吗？他们有笔记本吗？是的，他们有。是的，他们有。l6.让我看一看。让我看一看。Does he have an English English dictionary?No,he doesnt.He has an English Chinese dictionary?Do they have any note books?Yes,they do.Lets
10、have a look.Does he have a tennis racket?Yes,he does./No,he doesnt.Does she have a soccer ball?Yes,she does./No,she doesnt.Does he have a basketball?Yes,he does.Do they have a puck?Yes,they do./No,they dont.ice hockeyA:I want to play baseball.Do you have a baseball bat?B:No,I dont.A:Does your brothe
11、r have one?B:Yes,he does.Lets go and find him.Lets play volleyball.That sounds good.Lets play barbell.BarbellThat sounds boring.Lets play bowling.That sounds interesting.Lets play baseball.That sounds difficult.Lets go skateboarding.That sounds fun.(exciting)Lets play Ping Pong.That sounds relaxing.
12、let sb.do sth.Lets have a break.Lets go and play Ping-pong.Our School Sports Center needs new members.Fill in the enrollment form if you want to join the clubs.First name _ Last name _Age _ Sex _Class _ Club _Reason _Whats your first name,please?How old are you?What class are you in?What club do you
13、 want to join?Why?(Because I like)l写出反义词写出反义词ldislike_ interesting _ good_ well_ easy_ lost _lday _ different _lbig _ first _lon _ in front of _lthis _ these _lbring _lFill in the blanks1.A:Excuse me,_ you _ a baseball?lB:No,I _.lA:_ Jim _ one?lB:Yes,he _.Lets go and find him.2.A:Hi,Sally.B:Hi,Jane.
14、A:Sally,_ _ my friend,Lucy.B:Hi,Lucy._ to meet you.C:Nice to _ you,_.do havedontDoes havedoesthis isNice meet toolA:Lets play volleyball.lB:That _ interesting,but I _ have one.lA:Well,_ you have a tennis bat?lB:Yes,I _.Lets go and play tennis.lA:Thats a good _.soundsdontdodoidea1.Does B have an eras
15、er?2.Is the shop open?3.What day is today?4.What can they do?No,she doesnt.No,it isnt.It is closed.Today is Friday.They go to the supermarket.Part 11.What would B like?2.How much money does B have?3.Where is her purse?4.What does she do?She only has two yuan.Her purse is at home.She borrows four yua
16、n from C.Part 2Shed like a red pencil and a pencil-sharpener.1.Does Jim have a dictionary?2.Does Ann have a dictionary?3.Who has an English-Chinese dictionary?4.When can Li Lei give it back?Part 3No,he doesnt.Lucy has one.He can give it back next Monday.No,she doesnt.close *closed 1.The shop closes
17、at 8 pm.2.Please close the door.3.The door is closed.4.The shop is closed.5.The shop is open.borrow from 1.I borrow a book from him.2.May I borrow a pen from you?3.Dont borrow money from her.May I 1.May I come in?2.May I borrow a pen from you?3.May I sit down?give back (to sb.)1.Please give the mone
18、y back tomorrow.2.I can give the book back to him next week.3.Can you give my dictionary back this afternoon?There is something wrong with1.There is something wrong with my TV/his pen/your computer.2.There is something wrong with him/her/you/the boy.3.Whats wrong with you?4.Whats wrong with your TV?
19、close *closed borrow from May I give back (to sb.)There is something wrong withYou are going to have a P.E class,think about some activities.Talk about them.lTime _ lPlace _lSport _lReason _WritinglWrite a passage about yourself and your friend.lWhat sports do you play?What sports things do you have
20、?What other things do you do?lWhat about your friend?(parent)Key Key points:points:Food Do you like bananas?Does he/she like bananas?Do you like bananas Do you like bananas?Do you like oranges?Yes,I do.No,I dont.Does he like apples?Yes,he does.No,he doesnt.Does she like peaches?Yes,she does.No,she d
21、oesnt.Do they like grapes?Yes,they do.No,they dont.I like hamburgers for breakfast.But I dont like eggs.Do your parents like pizza?Yes,they do.No,they dont.Does your father like beer?Yes,he does.No,he doesnt.Choose the right words.1.There are five _(tomatoes,tomato)on the table.2.The _(child,childre
22、n)are in the room.3.She _(doesnt like,dont like)chicken for lunch.4.He _(likes,like)hamburgers.5.Do they_(likes,like)apples?6.Mike doesnt like_(bananas,banana).7.My mother doesnt have _(a lunch,lunch)at home.8.Does she _(like,likes)French fries?用所给动词的适当形式填空。1.She _(not like)salad.2._you _(like)orang
23、es?3.He _(eat)lots of healthy food every day.4.There _(be)some chicken on the plate.5.His mother_(like)ice cream.6._your father _(like)eggs for breakfast?7.They_(not like)playing tennis.8.There_(be)some potatoes in the bag.9.My mother_(have)supper at home every day.10.Mr.Green_(not have)lunch at sch
24、ool every day.A:Do you want to go to a movie?B:Yes,I do.That sounds good.A:What kind of movies do you like?B:I like action movies because they are exciting.And I think cartoons are interesting.A:How about thrillers?B:No.Thrillers are scary.How about you?A:I dont like thrillers,either.But I like documentaries.I think theyre instructive.Does he want to go to a movie?Yes,he does./No,he doesnt.What kind of movies does he want to see?He wants to see a comedy.What do you like to do on holidays?Why do you like?