cos210度等于几分之几 _求210度，225度，270度，300度，330度，360度的三角函数值，用分数表示

cos210度等于几分之几

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你好cos210度=cos（180度+30度）=-cos30度=-（根号3）/2如还不明白，请继续追问。如果你认可我的回答，请及时点击【采纳为满意回答】按钮手机提问的朋友在客户端右上角评价点【满意】即可。
求210度，225度，270度，300度，330度，360度的三角函数值，用分数表示

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sin
sin、cos、tan210度225度、240度300度315度

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都是些很简单的角度计算啊，你用三角定理分解一下就是了。210=180+30225=180+45240=180+60或者借用上面算出来的210的结果分解为240=210+30300=210+90=240+60=180+120=360-60 随便一种分解方法都可以计算出来。
315=225+90=360-45然后用正弦定理、余弦定理等等代入计算就是了。
急！！！数学题？？

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奇变偶不变，符号看象限cos210°=cos（π+π/6）=-cosπ/6=-『3/2【不会打根号，『就代替根号了】210°=π+π/6，π是π/2的偶数倍，∴cos210°与cosπ/6数值相同，∵210°在第三象限，∴cos210°是负值，∴cos210°=-cosπ/6再如cos（-π/6）-π/6在第四象限，∴cos（-π/6）是正值，即cos（-π/6）=cosπ/6=『3/2记住奇变偶不变，符号看象限就行了至于263度42分，我都忘了度与分的关系了你自己看吧
三角函数值列个表给我。。谢

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给你两个表，第一个是5°至360°每隔5°的角的正弦、余弦、正切、余切函数的高精度近似值。第二个是0°、15°、18°、30°、36°、45°、54°、60°、72°、75°、90°这些角的正弦、余弦、正切函数精确值的数学表达式。
其他角的三角函数精确值的数学表达式一般极其复杂，故未收录。
90°以上角的三角函数可借助此表用诱导公式求出。==================================================以下是第一个表：sin5° = 0.0871557427476582; cos5° = 0.996194698091746;tan5° = 0.087488663525924; cot5° = 11.4300523027613;sin10° = 0.17364817766693; cos10° = 0.984807753012208;tan10° = 0.176326980708465; cot10° = 5.67128181961771;sin15° = 0.258819045102521; cos15° = 0.965925826289068;tan15° = 0.267949192431123; cot15° = 3.73205080756888;sin20° = 0.342020143325669; cos20° = 0.939692620785908;tan20° = 0.363970234266202; cot20° = 2.74747741945462;sin25° = 0.422618261740699; cos25° = 0.90630778703665;tan25° = 0.466307658154999; cot25° = 2.14450692050956;sin30° = 0.5; cos30° = 0.866025403784439;tan30° = 0.577350269189626; cot30° = 1.73205080756888;sin35° = 0.573576436351046; cos35° = 0.819152044288992;tan35° = 0.70020753820971; cot35° = 1.42814800674211;sin40° = 0.642787609686539; cos40° = 0.766044443118978;tan40° = 0.83909963117728; cot40° = 1.19175359259421;sin45° = 0.707106781186547; cos45° = 0.707106781186548;tan45° = 1; cot45° = 1;sin50° = 0.766044443118978; cos50° = 0.642787609686539;tan50° = 1.19175359259421; cot50° = 0.83909963117728;sin55° = 0.819152044288992; cos55° = 0.573576436351046;tan55° = 1.42814800674211; cot55° = 0.70020753820971;sin60° = 0.866025403784439; cos60° = 0.5;tan60° = 1.73205080756888; cot60° = 0.577350269189626;sin65° = 0.90630778703665; cos65° = 0.422618261740699;tan65° = 2.14450692050956; cot65° = 0.466307658154999;sin70° = 0.939692620785908; cos70° = 0.342020143325669;tan70° = 2.74747741945462; cot70° = 0.363970234266202;sin75° = 0.965925826289068; cos75° = 0.258819045102521;tan75° = 3.73205080756888; cot75° = 0.267949192431123;sin80° = 0.984807753012208; cos80° = 0.17364817766693;tan80° = 5.67128181961771; cot80° = 0.176326980708465;sin85° = 0.996194698091746; cos85° = 0.0871557427476584;tan85° = 11.4300523027613; cot85° = 0.0874886635259242;sin90° = 1; cos90° = 0;tan90° = ∞; cot90° = 0;sin95° = 0.996194698091746; cos95° = -0.0871557427476582;tan95° = -11.4300523027613; cot95° = -0.0874886635259241;sin100° = 0.984807753012208; cos100° = -0.17364817766693;tan100° = -5.67128181961771; cot100° = -0.176326980708465;sin105° = 0.965925826289068; cos105° = -0.258819045102521;tan105° = -3.73205080756888; cot105° = -0.267949192431123;sin110° = 0.939692620785908; cos110° = -0.342020143325669;tan110° = -2.74747741945462; cot110° = -0.363970234266202;sin115° = 0.90630778703665; cos115° = -0.422618261740699;tan115° = -2.14450692050956; cot115° = -0.466307658154998;sin120° = 0.866025403784439; cos120° = -0.5;tan120° = -1.73205080756888; cot120° = -0.577350269189625;sin125° = 0.819152044288992; cos125° = -0.573576436351046;tan125° = -1.42814800674212; cot125° = -0.700207538209709;sin130° = 0.766044443118978; cos130° = -0.642787609686539;tan130° = -1.19175359259421; cot130° = -0.83909963117728;sin135° = 0.707106781186548; cos135° = -0.707106781186547;tan135° = -1; cot135° = -1;sin140° = 0.642787609686539; cos140° = -0.766044443118978;tan140° = -0.83909963117728; cot140° = -1.19175359259421;sin145° = 0.573576436351046; cos145° = -0.819152044288992;tan145° = -0.70020753820971; cot145° = -1.42814800674211;sin150° = 0.5; cos150° = -0.866025403784439;tan150° = -0.577350269189626; cot150° = -1.73205080756888;sin155° = 0.4226182617407; cos155° = -0.90630778703665;tan155° = -0.466307658154999; cot155° = -2.14450692050956;sin160° = 0.342020143325669; cos160° = -0.939692620785908;tan160° = -0.363970234266203; cot160° = -2.74747741945462;sin165° = 0.258819045102521; cos165° = -0.965925826289068;tan165° = -0.267949192431123; cot165° = -3.73205080756887;sin170° = 0.173648177666931; cos170° = -0.984807753012208;tan170° = -0.176326980708465; cot170° = -5.6712818196177;sin175° = 0.0871557427476582; cos175° = -0.996194698091746;tan175° = -0.087488663525924; cot175° = -11.4300523027613;sin180° = 0; cos180° = -1;tan180° = 0; cot180° = ∞;sin185° = -0.0871557427476579; cos185° = -0.996194698091746;tan185° = 0.0874886635259238; cot185° = 11.4300523027614;sin190° = -0.17364817766693; cos190° = -0.984807753012208;tan190° = 0.176326980708465; cot190° = 5.67128181961771;sin195° = -0.25881904510252; cos195° = -0.965925826289068;tan195° = 0.267949192431122; cot195° = 3.73205080756888;sin200° = -0.342020143325669; cos200° = -0.939692620785908;tan200° = 0.363970234266202; cot200° = 2.74747741945462;sin205° = -0.422618261740699; cos205° = -0.90630778703665;tan205° = 0.466307658154998; cot205° = 2.14450692050956;sin210° = -0.5; cos210° = -0.866025403784439;tan210° = 0.577350269189626; cot210° = 1.73205080756888;sin215° = -0.573576436351046; cos215° = -0.819152044288992;tan215° = 0.700207538209709; cot215° = 1.42814800674212;sin220° = -0.642787609686539; cos220° = -0.766044443118978;tan220° = 0.83909963117728; cot220° = 1.19175359259421;sin225° = -0.707106781186547; cos225° = -0.707106781186548;tan225° = 1; cot225° = 1;sin230° = -0.766044443118978; cos230° = -0.642787609686539;tan230° = 1.19175359259421; cot230° = 0.83909963117728;sin235° = -0.819152044288992; cos235° = -0.573576436351046;tan235° = 1.42814800674211; cot235° = 0.70020753820971;sin240° = -0.866025403784438; cos240° = -0.5;tan240° = 1.73205080756888; cot240° = 0.577350269189626;sin245° = -0.90630778703665; cos245° = -0.422618261740699;tan245° = 2.14450692050956; cot245° = 0.466307658154998;sin250° = -0.939692620785908; cos250° = -0.342020143325669;tan250° = 2.74747741945462; cot250° = 0.363970234266203;sin255° = -0.965925826289068; cos255° = -0.258819045102521;tan255° = 3.73205080756888; cot255° = 0.267949192431123;sin260° = -0.984807753012208; cos260° = -0.17364817766693;tan260° = 5.67128181961771; cot260° = 0.176326980708465;sin265° = -0.996194698091746; cos265° = -0.0871557427476582;tan265° = 11.4300523027613; cot265° = 0.0874886635259241;sin270° = -1; cos270° = 0;tan270° = ∞; cot270° = 0;sin275° = -0.996194698091746; cos275° = 0.0871557427476579;tan275° = -11.4300523027614; cot275° = -0.0874886635259237;sin280° = -0.984807753012208; cos280° = 0.17364817766693;tan280° = -5.67128181961772; cot280° = -0.176326980708465;sin285° = -0.965925826289068; cos285° = 0.25881904510252;tan285° = -3.73205080756888; cot285° = -0.267949192431122;sin290° = -0.939692620785908; cos290° = 0.342020143325669;tan290° = -2.74747741945462; cot290° = -0.363970234266203;sin295° = -0.90630778703665; cos295° = 0.422618261740699;tan295° = -2.14450692050956; cot295° = -0.466307658154998;sin300° = -0.866025403784439; cos300° = 0.5;tan300° = -1.73205080756888; cot300° = -0.577350269189626;sin305° = -0.819152044288992; cos305° = 0.573576436351046;tan305° = -1.42814800674211; cot305° = -0.70020753820971;sin310° = -0.766044443118978; cos310° = 0.642787609686539;tan310° = -1.19175359259421; cot310° = -0.83909963117728;sin315° = -0.707106781186548; cos315° = 0.707106781186547;tan315° = -1; cot315° = -1;sin320° = -0.64278760968654; cos320° = 0.766044443118978;tan320° = -0.839099631177281; cot320° = -1.19175359259421;sin325° = -0.573576436351046; cos325° = 0.819152044288992;tan325° = -0.70020753820971; cot325° = -1.42814800674211;sin330° = -0.5; cos330° = 0.866025403784438;tan330° = -0.577350269189627; cot330° = -1.73205080756887;sin335° = -0.422618261740699; cos335° = 0.90630778703665;tan335° = -0.466307658154998; cot335° = -2.14450692050956;sin340° = -0.342020143325669; cos340° = 0.939692620785908;tan340° = -0.363970234266203; cot340° = -2.74747741945462;sin345° = -0.258819045102521; cos345° = 0.965925826289068;tan345° = -0.267949192431123; cot345° = -3.73205080756888;sin350° = -0.17364817766693; cos350° = 0.984807753012208;tan350° = -0.176326980708465; cot350° = -5.67128181961771;sin355° = -0.0871557427476583; cos355° = 0.996194698091746;tan355° = -0.0874886635259241; cot355° = -11.4300523027613;sin360° = 0; cos360° = 1;tan360° = 0; cot360° = ∞;==================================================关于第二个表的注释：“sqrt(x)”表示x的算术平方根，“/”表示除号。