已知Tanx等于负根号3.求sinx,cosx的值
\u5df2\u77e5tanX\u7b49\u4e8e\u8d1f\u6839\u53f73\uff0c\u600e\u6837\u6c42sinX\uff0ccosX\u7684\u503c\u3002tanx=sinx/cosx=-\u221a3\uff1b sinx=-\u221a3cosx\uff1b (sinx)^2+(cosx)^2=1\uff1b (cosx)^2=1/4\uff1b \u5f53cosx=-1/2\uff1bsinx=\u221a3/2 \u5f53cosx=1/2 \uff1bsinx=-\u221a3/2\u221a\u8868\u793a\u6839\u53f7
tanx=-\u221a3
sinx=-\u221a3cosx
(sinx)^2=3(cosx)^2
4(cosx)^2=1
(cosx)^2=1/4
\u4e24\u89e3\u5206\u522b\u4e3a sinx=\u221a3/2 cosx=-1/2
sinx=-\u221a3/2 cosx=1/2
负二分之根号三，负三分之根号三
绛旓細120掳,-60掳
绛旓細瑙ｏ細鈭tanx=鈭3 鈭磗inx/cosx=tanx=鈭3(1)鍙堚埖锛坰inx)^2+(cosx)^2=1(2)涓攛鍦ㄧ涓夎薄闄 鈭磗inx<0,cos<0 鐢憋紙1锛夊拰锛2锛夎В寰 sinx=-鈭3/2,cosx=-1/2 鈭磗inx-cosx=-鈭3/2-1/2=-(鈭3-1)/2
绛旓細{x|x=k蟺-蟺/3 k灞炰簬z}
绛旓細arctan锛-鈭3锛夆埓tanx=-鈭3锛寈=2蟺du/3+k蟺鈭5蟺/3+k蟺銆傚嵆x鏄浜岋紝绗洓璞￠檺闆嗗悎鐨勮銆俛rctan(-鏍瑰彿3锛=蟺-arctan(鏍瑰彿3锛=蟺-蟺/3 =2蟺/3
绛旓細瑙ｏ細鈭tanx=鈭3 鈭磗inx/cosx=tanx=鈭3(1)鍙堚埖锛坰inx)^2+(cosx)^2=1(2)涓攛鈭(蟺,3/2蟺) 鍗冲湪绗笁璞￠檺 鈭磗inx<0,cos<0 鐢憋紙1锛夊拰锛2锛夎В寰 sinx=-鈭3/2 cosx=-1/2 鈭磗inx-cosx=-鈭3/2-1/2=-(鈭3-1)/2
绛旓細鈭 cosx=卤4/5 (蟺/2锛渪锛溝 ,鍙栤-鈥濓紱 3蟺/2锛渪锛2蟺,鍙栤+鈥).sinx=1/cscx=卤1/鈭(1+ctg^2x).鈭磗inx=卤3/5. 锛 蟺/2<x <蟺 锛屽彇鈥+鈥濓紱 3蟺/2<x<2蟺 锛屽彇鈥-鈥濓級銆(鍥犳湭鐗规寚x鐨勮薄闄愶紝鐢tanx=-3/4,鍙垽鏂瓁鎴栧湪绗簩璞￠檺锛屾垨鍦ㄧ鍥涜薄闄愶紝鏁呮湁鈥+鈥...
绛旓細120掳, -60掳
绛旓細{x|x=k蟺-蟺/3 k灞炰簬z}
绛旓細arctan锛-鈭3锛=x锛熶綘鍐欓敊浜嗐傚洜涓簍anx=鈭3锛寈=60掳锛岃tanx涓濂囧嚱鏁帮紝鎵浠ワ細瀵逛簬x=tarctan锛-鈭3锛=2k蟺-60掳=2k蟺-蟺/3銆
绛旓細tanx=鏍瑰彿涓3,蟺<X<3/2蟺,鐢辨鍙煡X=蟺 + arctan锛堟牴鍙蜂笅3锛夛紱X=蟺+蟺/3=4蟺/3;cosx-sinx=sin(蟺/3)-cos(蟺/3)=(鏍瑰彿涓3-1)/2
