江苏省苏州市初三数学期终复习课时作业三、锐角三角函数和解直角三角形(含详细答案)

清水混凝土的配合比设计中，要针对当地水泥、砂石、外掺料及外加剂等原材料影响混凝土质量的多种因素进行分析，确定主要控制因素，并从经济性和使用要求综合考虑，优选出符合生产条件的最优方案组合。obstacles,correctingmisunderstandings,advocategoodcadrestyle.2,adheretothescientificdecision-makinganddemocraticdecision-makingdecision-makinglaw.Correctlyhandletoensurethatgovernmentdecreesandbasedontheactualcreativework,givingfullplaytosubjectiveinitiative,putanendtoimplementtheconferencemeeting,todocumenttheimplementationofdocumentsetc.Improvethescientificanddemocraticdecision-makingmechanism,improveandimplementthedecisiontosolicittheviewsofexperts,thepublichearingsystem.Improvetheimportantdecisionofriskassessmentmechanismandlegalreviewmechanism.3,topromoteteamunity.Upholdandimprovethesystemofannualpartybooktalkhearttoheart,mindandPartymembers,Partymemberstoexchangeeachothernotlessthan2times.Theimplementationofsoundteamdemocraticlifesystem,consolidateandenhancetheparty'smasslineeducationalpracticewillpromotetheachievementofthetopicofdemocraticlife,criticismandself-criticismnormalization,along-term.Adheretothepartyonthebasisoftheprincipleofunity,enhanceinternalcommunication,strengtheninternalsupervision,selfSleepmaintenanceteamcollectiveimageandauthority.(three)toensuretheexecutionisnotstrongordisguisedtoresistgovernmentdecreesissues.IndividualBureauleadershipteammemberslackoflearningpoliticaltheorysystem,notfromtheobjectivereality,notwiththeparty'sinterestsabovealltheprinciplestodealwithpersonalproblems.Inthespecificworksafetysupervisionintheexecutionisnotstrong,intheimplementationofthedecisiontodeploythediscount,makechoices,engageinwork,theimplementationoftheagreement,uncomfortableisnotperformed,openordisguisedtoresist,thelackofsubjectconsciousnessofthepartyorganization,thelackofresistinsocietyallkindsofbadhabitsandunwholesometendenciesofcourageGasandcourage.Suchastheliabilityinsuranceofsafeproductionwork,individualleadersthathavesomeonearrested,andnofunding,notintheglobalchessperspectivetothecountrysidetocarryoutdailyinspection,foundnoneofmybusinessacceptanceoftheresumptionofproductioninanarmchair,withapen,indifferent.Correctivemeasures:(LEDLeadership:LuoMingjun,rectificationtime:beforeSeptember25th,insistforalongtime)1,tostrengthenthesenseofresponsibility,worktosolvethelackofdecentoccupationexplainaway,conductproblems.Toestablishtheoverallconcept,eliminatedepartmentalism.Strictassessmentandaccountability,tosolvethespiritualslack,nianqingpazhong,statusquo,Toestablishandperfectthemuddlealongandotherissues.Bureaustaffconductworkregulations,standardizethebehaviorofpersonnel.2,strengthentheresponsibilitysystem.Oneisthein-depthstudyandimplementtheHunanprovincialPartyandgovernmentleadingcadresInterimProvisionsontheworksafetyofapairof(HunanOfficeissued2013No.课时作业三、锐角三角函数和解直角三角形考点一：锐角三角函数的概念（1）在Rt△ABC中，∠C=90º，∠A、∠B、∠C的对边分别为a、b、c，则sinA=；cosA=；tanA=。(2)sinA,cosA,tanA是比值，注意比的顺序；(3)sinA,cosA,tanA没有单位考点二：锐角三角函数之间的关系sin(90°-A)=cosAcos(90°-A)=sinAtan(90°-A)=cotAcot(90°-A)=tanA平方关系：sin2A+cos2A=1倒数关系：tanA•tan(900-A)=1正余弦及正切之间的关系：tanA=sinA/cosA考点三：特殊的三角函数值的计算sinacosatana30º45º60º①正弦、余弦的增减性：当0°≤≤90°时，sin随的增大而增大，cos随的增大而减小。②正切的增减性：当0°90°时，tan随的增大而增大。考点四：解直角三角形解直角三角形的定义：已知边和角（两个，其中必有一边）→所有未知的边和角。依据：①边的关系：222cba；②角的关系：A+B=90°；③边角关系：三角函数的定义。(注意：尽量避免使用中间数据和除法)应用举例：(1)仰角：视线在水平线上方的角；俯角：视线在水平线下方的角。仰角铅垂线水平线视线视线俯角(2)坡面的铅直高度h和水平宽度l的比叫做坡度(坡比)。用字母i表示，即hil。坡度一般写成1:m的形式，如1:5i等。把坡面与水平面的夹角记作(叫做坡角)，那么tanhil。3、从某点的指北方向按顺时针转到目标方向的水平角，叫做方位角。如图3，OA、OB、OC、OD的方向角分别是：45°、135°、225°。4、指北或指南方向线与目标方向线所成的小于90°的水平角，叫做方向角。如图4,OA、OB、OC、OD的方向角分别是：北偏东30°（东北方向），南偏东45°（东南方向），南偏西60°（西南方向），北偏西60°（西北方向）。清水混凝土的配合比设计中，要针对当地水泥、砂石、外掺料及外加剂等原材料影响混凝土质量的多种因素进行分析，确定主要控制因素，并从经济性和使用要求综合考虑，优选出符合生产条件的最优方案组合。obstacles,correctingmisunderstandings,advocategoodcadrestyle.2,adheretothescientificdecision-makinganddemocraticdecision-makingdecision-makinglaw.Correctlyhandletoensurethatgovernmentdecreesandbasedontheactualcreativework,givingfullplaytosubjectiveinitiative,putanendtoimplementtheconferencemeeting,todocumenttheimplementationofdocumentsetc.Improvethescientificanddemocraticdecision-makingmechanism,improveandimplementthedecisiontosolicittheviewsofexperts,thepublichearingsystem.Improvetheimportantdecisionofriskassessmentmechanismandlegalreviewmechanism.3,topromoteteamunity.Upholdandimprovethesystemofannualpartybooktalkhearttoheart,mindandPartymembers,Partymemberstoexchangeeachothernotlessthan2times.Theimplementationofsoundteamdemocraticlifesystem,consolidateandenhancetheparty'smasslineeducationalpracticewillpromotetheachievementofthetopicofdemocraticlife,criticismandself-criticismnormalization,along-term.Adheretothepartyonthebasisoftheprincipleofunity,enhanceinternalcommunication,strengtheninternalsupervision,selfSleepmaintenanceteamcollectiveimageandauthority.(three)toensuretheexecutionisnotstrongordisguisedtoresistgovernmentdecreesissues.IndividualBureauleadershipteammemberslackoflearningpoliticaltheorysystem,notfromtheobjectivereality,notwiththeparty'sinterestsabovealltheprinciplestodealwithpersonalproblems.Inthespecificworksafetysupervisionintheexecutionisnots