为什么sin120等于cos30
sin-120 sin-30 cos-30\u90fd\u600e\u4e48\u7b97\u51fa\u6765\u7684\uff1f-1/2*-1/2*\u4e8c\u5206\u4e4b\u6839\u53f73=\u516b\u5206\u4e4b\u6839\u53f73
\u4e8c\u5206\u4e4b\u6839\u53f7\u4e09\uff0c\u8fd9\u4e2a\u662f\u5e38\u8bc6\u4e0d\u7528\u6c42\u8bc1
sin(π/2+30)=sin(π/2-30)=cos30
sin120=sin60,sin60=con30
绛旓細tan120搴=sin120搴/cos120搴=-sin(180-120)搴/cos(180-120)搴=-sin60搴/cos60搴=-(鈭3/2)/(1/2)=-鈭3銆倀an鏄姝ｅ垏鍑芥暟鏄洿瑙掍笁瑙掑舰涓紝瀵硅竟涓庨偦杈圭殑姣斿硷紝鏀惧湪鐩磋鍧愭爣绯讳腑鍗硉an胃=y/x銆備笁瑙掑嚱鏁扮殑瀹氫箟涓夎鍑芥暟鏄熀鏈垵绛夊嚱鏁颁箣涓锛屾槸浠ヨ搴︿负鑷彉閲忥紝瑙掑害瀵瑰簲浠绘剰瑙掔粓杈逛笌鍗曚綅鍦嗕氦鐐瑰潗鏍...
绛旓細鍥犱负sin(180-60)=sin180+sin(-60)锛屽叾娆in鍑芥暟鍦ㄧ涓璞￠檺鏄鍗曡皟閫掑鐨勪粠0鍒1锛岀浜岃薄闄愭槸閫掑噺鐨勪粠1鍒0锛屾墍浠sin120掳绛変簬sin60掳銆備笁瑙掑嚱鏁版槸鏁板涓睘浜庡垵绛夊嚱鏁颁腑鐨勮秴瓒婂嚱鏁扮殑涓绫诲嚱鏁般傚畠浠殑鏈川鏄换鎰忚鐨勯泦鍚堜笌涓涓瘮鍊肩殑闆嗗悎鐨勫彉閲忎箣闂寸殑鏄犲皠銆傞氬父鐨勪笁瑙掑嚱鏁版槸鍦ㄥ钩闈㈢洿瑙掑潗鏍囩郴涓畾涔夌殑锛屽叾...
绛旓細cos90搴=0锛sin90搴=1 鍦ㄧ洿瑙掍笁瑙掑舰涓紝褰撳钩闈笂鐨勪笁鐐笰銆丅銆丆鐨勮繛绾匡紝AB銆丄C銆丅C锛屾瀯鎴愪竴涓洿瑙掍笁瑙掑舰锛屽叾涓垹ACB涓虹洿瑙掋傚鈭燘AC鑰岃█锛屽杈癸紙opposite锛塧=BC銆佹枩杈癸紙hypotenuse锛塩=AB銆侀偦杈癸紙adjacent锛塨=AC銆傚湪骞抽潰鐩磋鍧愭爣绯粁Oy涓鈭犖茬殑濮嬭竟涓簒杞寸殑姝ｅ崐杞达紝璁剧偣P锛坸锛寉锛変负鈭犖茬殑...
绛旓細Sin120掳锛濃垰3/2銆cos120掳锛濓紞1/2銆俆an120掳锛濓紞鈭3銆傛妸姝ｅ鸡锛屼綑寮︼紝姝ｅ垏鐨勪笁瑙掑嚱鏁板浘鐢诲嚭鏉ワ紝妯潗鏍囦唬琛ㄨ搴︼紝绾靛潗鏍囦唬琛ㄧ粨鏋滐紝鍙互鎶婃瘡涓偣鍦ㄥ潗鏍囪酱涓婃爣绀哄嚭鏉ャ
绛旓細120鐨勫垎鍒簩鍒嗕箣鏍瑰彿涓夛紝浜屽垎涔嬩竴锛岃礋鏍瑰彿涓夈135鐨勬槸浜屽垎涔嬫牴鍙蜂簩锛岃礋浜屽垎涔嬫牴鍙蜂簩锛岃礋涓銆350姝ｅ湪绠椼
绛旓細涓婇潰 涔熷彲浠ユ帹锛屾牴鎹(sin伪)^2+(cos伪)^2=1 涓洪伩鍏嶈浼氾紝鎴戜笓闂ㄦ墦涓婃嫭鍙凤紝杩欎釜浣犲簲璇ュ緢鐔熸倝 鏍规嵁杩欎釜绠楋紝sin伪=卤0.8锛屽洜涓哄湪绗竴璞￠檺锛屾墍浠ュ彇姝ｏ紝sin伪=0.8 sin(伪+120掳)=sin伪cos120掳+cos伪sin120掳 (cos120掳=-cos60掳=-1/2,sin120掳=sin60掳=鈭3/2,sin伪=0.8,cos伪=0...
绛旓細tan120掳=-鈭3銆傝В绛旇繃绋嬪涓嬶細tan120掳 =sin120掳/cos120掳 =-sin(180-120)掳/cos(180-120)掳 =-sin60掳/cos60掳 =-(鈭3/2)/(1/2)=-鈭3
绛旓細sin90=1;cos90=0;tan90=+鈭烇紱sin120=鈭3/2;cos120=-1/2,tan120=-鈭3;sin135=鈭2/2;cos120=-鈭2/2,tan120=-1;sin150=1/2;cos150=-鈭3/2,tan150=-鈭3/3;sin180=0;cos180=-1,tan180=0;
绛旓細(姝ｅ鸡) Sin 胃 = 瀵硅竟A / 鏂滆竟C
绛旓細sin160=sin20=cos70 sin150=sin30=cos60 鈥︹in100=sin80=cos10 鎵浠ュ師寮=(sin10cos10)(sin20cos20)(sin30cos30)鈥︹︼紙sin80cos80锛塻in90 =sin20 sin40 sin60 sin80 sin100 sin120 sin140 sin160 sin90/(2^8) (鐢2鍊嶈鍏紡)4*sin20sin80sin40=sin60(鐢3鍊嶈鍏紡)sin(60-...
