sin(-90°）等于多少？ sin90度是多少，为什么？
sin(\u03b1-90\u00b0\uff09\u7b49\u4e8e\u4ec0\u4e48\uff1fsin\uff08a-90\u00b0\uff09\u9996\u5148\u5c06\u4e09\u89d2\u7b26\u53f7\u6539\u4e3acos\uff0c\u7b26\u53f7\u770b\u8c61\u9650\uff0c\u82e5a\u4e3a\u7b2c\u4e00\u8c61\u9650\u5219a-90\u4e3a\u7b2c\u56db\u8c61\u9650\uff0csin\u4e3a\u8d1f\uff0c\u6545sin\uff08a-90\u00b0\uff09=-cosa
\u7b2c\u4e8c\u4e2a\u95ee\u9898\uff0c\u5c062x\u770b\u6210\u4e0a\u8ff0a,\u5f97\u5230sin\uff082x+150\u00b0\uff09=-cos\uff082x+240\u00b0\uff09=cos\uff082x+60\u00b0\uff09
\u6240\u4ee5?=60\u00b0+k•360\u00b0,k\u662f\u6574\u6570
sin90º=1\uff0ccos0º=1\uff0ccos90º=0\uff0ccos180º=-1\uff0ccos270º=0\uff0ccos360º=1.tan0º=0\uff0ctan90º\u4e0d\u5b58\u5728\uff0ctan180º=0\uff0ctan270º\u4e0d\u5b58\u5728\uff0ctan360º=0\u3002
\u4e09\u4ef6\u51fd\u6570\u53ef\u4ee5\u4f9d\u636e\u534a\u5f84\u4e3a1\u4e2d\u5fc3\u4e3a\u539f\u70b9\u7684\u5355\u4f4d\u5706\u6765\u5b9a\u4e49\u3002\u56fe\u50cf\u4e2d\u7ed9\u51fa\u4e86\u7528\u5f27\u5ea6\u5ea6\u91cf\u7684\u4e00\u4e9b\u5e38\u89c1\u7684\u89d2:\u9006\u65f6\u9488\u65b9\u5411\u7684\u5ea6\u91cf\u662f\u6b63\u89d2\uff0c\u800c\u987a\u65f6\u9488\u7684\u5ea6\u91cf\u662f\u8d1f\u89d2\u3002
\u8bbe\u4e00\u4e2a\u8fc7\u539f\u70b9\u7684\u7ebf\uff0c\u540cx\u8f74\u6b63\u534a\u90e8\u5206\u5f97\u5230\u4e00\u4e2a\u89d2\u03b8\uff0c\u5e76\u4e0e\u5355\u4f4d\u5706\u76f8\u4ea4\u3002\u8fd9\u4e2a\u4ea4\u70b9\u7684x\u548cy\u5750\u6807\u5206\u522b\u7b49\u4e8ecos\u03b8\u548csin\u03b8\u3002\u56fe\u50cf\u4e2d\u7684\u4e09\u89d2\u5f62\u786e\u4fdd\u4e86\u8fd9\u4e2a\u516c\u5f0f\uff1b\u534a\u5f84\u7b49\u4e8e\u659c\u8fb9\u4e14\u957f\u5ea6\u4e3a1\uff0c\u6240\u4ee5\u6709 sin\u03b8=y/1 \u548c cos\u03b8=x/1\uff0c\u540c\u65f6\u6839\u636e\u6b63\u5207\u51fd\u6570\u7684\u5b9a\u4e49\u6709tan\u03b8=sin\u03b8/cos\u03b8=y/x\u3002
\u6839\u636e\u6b64\u5b9a\u4e49\uff0c\u53ef\u5f97\uff1a
\u5f53\u6240\u6c42\u89d2\u4e3a0º\u65f6\uff0c\u5176x=1\uff0cy=0\uff0c\u5219sin0º=y/1=0\uff0ccos0º=x/1=1\uff0ctan0º=y/x=0\u3002
\u5f53\u6240\u6c42\u89d2\u4e3a90º\u65f6\uff0c\u5176x=0\uff0cy=1\uff0c\u5219sin90º=y/1=1\uff0ccos90º=x/1=0\uff0ctan90º=y/x=1/0\u4e0d\u5b58\u5728\u3002
\u5f53\u6240\u6c42\u89d2\u4e3a180º\u65f6\uff0c\u5176x=-1\uff0cy=0\uff0c\u5219sin180º=y/1=0\uff0ccos180º=x/1=-1\uff0ctan0º=y/x=0\u3002
\u5f53\u6240\u6c42\u89d2\u4e3a270º\u65f6\uff0c\u5176x=\uff0cy=-1\uff0c\u5219sin90º=y/1=-1\uff0ccos90º=x/1=0\uff0ctan90º=y/x=-1/0\u4e0d\u5b58\u5728\u3002
\u5f53\u6240\u6c42\u89d2\u4e3a360º\u65f6\uff0c\u5176x=1\uff0cy=0\uff0c\u5219sin360º=y/1=0\uff0ccos360º=x/1=1\uff0ctan360º=y/x=0\u3002
\u6269\u5c55\u8d44\u6599\uff1a
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\u90a3\u4e48\u5411\u91cfMP\u5bf9\u5e94\u7684\u5c31\u662f\u03b1\u7684\u6b63\u5f26\u503c\uff0c\u5411\u91cfOM\u5bf9\u5e94\u7684\u5c31\u662f\u4f59\u5f26\u503c\u3002OP\u7684\u5ef6\u957f\u7ebf\uff08\u6216\u53cd\u5411\u5ef6\u957f\u7ebf\uff09\u4e0e\u8fc7A\u70b9\u7684\u5207\u7ebf\u7684\u4ea4\u70b9\u4e3aT\uff0c\u5219\u5411\u91cfAT\u5bf9\u5e94\u7684\u5c31\u662f\u6b63\u5207\u503c\u3002\u5411\u91cf\u7684\u8d77\u6b62\u70b9\u4e0d\u80fd\u98a0\u5012\uff0c\u56e0\u4e3a\u5176\u65b9\u5411\u662f\u6709\u610f\u4e49\u7684\u3002
\u501f\u52a9\u7ebf\u4e09\u89d2\u51fd\u6570\u7ebf\uff0c\u6211\u4eec\u53ef\u4ee5\u89c2\u5bdf\u5230\u7b2c\u4e8c\u8c61\u9650\u89d2\u03b1\u7684\u6b63\u5f26\u503c\u4e3a\u6b63\uff0c\u4f59\u5f26\u503c\u4e3a\u8d1f\uff0c\u6b63\u5207\u503c\u4e3a\u8d1f\u3002
\u53c2\u8003\u8d44\u6599\u6765\u6e90\uff1a\u767e\u5ea6\u767e\u79d1-\u4e09\u89d2\u51fd\u6570
sin(-x)=-sinx
所以，sin(-90)=-1
sin(-90°）=-sin(90°）=-1
sin(-90°）=-sin90°=-1
-1
绛旓細sin锛-90掳锛=-sin锛90掳锛=-1 鍦ㄧ洿瑙掍笁瑙掑舰涓紝浠绘剰涓閿愯鈭燗鐨勫杈逛笌鏂滆竟鐨勬瘮鍙仛鈭燗鐨勬寮︼紝璁颁綔sinA锛堢敱鑻辫sine涓璇嶇畝鍐欏緱鏉ワ級锛屽嵆sinA=鈭燗鐨勫杈/鏂滆竟銆傚湪RT鈻矨BC涓紝濡傛灉閿愯A纭畾锛岄偅涔堣A鐨勫杈逛笌鏂滆竟鐨勬瘮渚块殢涔嬬‘瀹氾紝杩欎釜姣斿彨鍋氳A鐨勬寮︼紝璁颁綔sinA锛屽嵆sinA=瑙扐鐨勫杈/瑙扐鐨勬枩杈...
绛旓細鎵浠ワ紝sin(-90)=-1
绛旓細-1 寤鸿浣犳妸鍗曚綅鍦嗘硶鎼炴噦锛岄偅灏变笉鎰佷笁瑙掑嚱鏁板间簡鍝埪仿仿
绛旓細sin(-90)鍗充粠x杞存鍗婅酱(濮嬭竟)閫嗘椂閽堣浆90搴锛屽垰濂藉湪y杞存鍗婅酱锛屽搴旂殑y鐨勫兼槸1 鍚岀悊锛宻in270鍦▂杞存鍗婅酱锛寉鍊间负1 cos180鍦▁杞磋礋鍗婅酱锛屽搴攛鍊间负-1
绛旓細棣栧厛sin(-x) = -sin(x) 杩欐槸鍏紡 鐒跺悗瑕佺煡閬搒in琛ㄧずy杞翠笂鐨勬暟 鎺ョ潃鐪嬪害鏁版槸90搴 姝ｆ寚鐫Y杞存鍗婅酱 鎵浠ユ槸姝ｄ竴銆愬鏋 鎸囩潃y璐熷崐杞村嵆270搴 灏辨槸璐熶竴銆戙愬鏋 搴︽暟鏄0鎴180 鍗虫寚鐫x杞 涓嶇姝ｈ礋 閮芥槸sin(x) =0 鍥犱负鍦▂杞翠笂 鎸囩潃鍘熺偣 銆戞墍浠in璐90搴绛変簬璐熶竴 ...
绛旓細sin锛-x锛=-sin锛坸锛夋墍浠sin锛-90锛=-sin锛90锛=-1
绛旓細sin270掳 =sin(360掳-90掳)=sin(-90掳)=-sin(90掳)=-1
绛旓細sin锛a-90掳锛棣栧厛灏嗕笁瑙掔鍙锋敼涓篶os锛岀鍙风湅璞￠檺锛岃嫢a涓虹涓璞￠檺鍒檃-90涓虹鍥涜薄闄愶紝sin涓鸿礋锛屾晠sin锛坅-90掳锛=-cosa 绗簩涓棶棰橈紝灏2x鐪嬫垚涓婅堪a,寰楀埌sin锛2x+150掳锛=-cos锛2x+240掳锛=cos锛2x+60掳锛夋墍浠?=60掳+k•360掳,k鏄暣鏁 ...
绛旓細sin270掳=sin锛90掳+180掳锛=-sin90掳=-1锛堣瀵煎叕寮忥級甯屾湜瀵逛綘鏈夋墍甯姪 杩樻湜閲囩撼~~
绛旓細0掳锛sin伪=0锛宑os伪=1锛宼an伪=0锛90掳锛歴in伪=1锛宑os伪=0锛宼an伪涓嶅瓨鍦紱180掳锛歴in伪=0锛宑os伪=-1锛宼an伪=0锛270掳锛歴in伪=-1锛宑os伪=0锛宼an伪涓嶅瓨鍦紱360掳锛歴in伪=0锛宑os伪=1锛宼an伪=0銆
