sinx－cosx等于多少？？，求帮忙？很急啊 数学中，“sinx-cosx”等于多少？
sinx\u548ccosx\u600e\u4e48\u6362\u7b97\uff1fcosx\uff0dsinx=\u221a2/2cosx-\u221a2/2sinx=\u221a2(1/2cosx-1/2sinx)=\u221a2(cos\u03c0/4cosx-sin\u03c0/4sinx)=\u221a2cos(x+\u03c0/4)
cosx\u4e0esinx\u53eb\u505a\u4f59\u5f26\u51fd\u6570\u548c\u6b63\u5f26\u51fd\u6570\uff0c\u5c5e\u4e8e\u4e09\u89d2\u51fd\u6570\uff0c\u662f\u57fa\u672c\u521d\u7b49\u51fd\u6570\u4e4b\u4e00\u3002
\u6269\u5c55\u8d44\u6599\uff1a\u5b9a\u4e49\u57df\u4e0e\u503c\u57df\u4e0e\u5468\u671f
sinx\uff0ccosx\u7684\u5b9a\u4e49\u57df\u4e3aR\uff0c\u503c\u57df\u4e3a[-1,1]\uff0c\u5468\u671fT=2\u03c0/\u03c9=2\u03c0
\u6b63\u5f26\u5b9a\u7406
\u5bf9\u4e8e\u8fb9\u957f\u4e3aa,b\u548cc\u800c\u76f8\u5e94\u89d2\u4e3aA,B\u548cC\u7684\u4e09\u89d2\u5f62\uff0c\u6709\uff1a
sinA / a = sinB / b = sinC/c
\u4e5f\u53ef\u8868\u793a\u4e3a\uff1a
a/sinA=b/sinB=c/sinC=2R
\u53d8\u5f62\uff1aa=2RsinA,b=2RsinB,c=2RsinC
\u5176\u4e2dR\u662f\u4e09\u89d2\u5f62\u7684\u5916\u63a5\u5706\u534a\u5f84
\u4f59\u5f26\u5b9a\u7406
\u5bf9\u4e8e\u8fb9\u957f\u4e3aa\u3001b\u3001c\u800c\u76f8\u5e94\u89d2\u4e3aA\u3001B\u3001C\u7684\u4e09\u89d2\u5f62\uff0c\u6709\uff1a
a² = b² + c²- 2bc\u00b7cosA
b² = a² + c² - 2ac\u00b7cosB
c² = a² + b² - 2ab\u00b7cosC
\u53c2\u8003\u8d44\u6599\uff1a\u767e\u5ea6\u767e\u79d1\u2014\u2014\u4e09\u89d2\u51fd\u6570
=√2(√2/2*sinx-√2/2cosx)
=√2(sinxcos45-cosxsin45)
=√2sin(x-45)
亲 记得采纳哦 O(∩_∩)O谢谢
sinx－cosx=√2(√2/2sinx－√2/2cosx)
=√2(sinxcosπ/4－cosxsinπ/4)
=√2sin(x-π/4)
sinxcosy-cosxsiny=sin（x-y)
绛旓細sinx-cosx=1/3 (sinx-cosx)^2=sin²x-2sinxcosx+cos²x=1-2sinxcosx=1/9 鎵浠 sinxcosx=4/9
绛旓細绛変簬0鍟 =锛岃皝璇翠笉绛変簬0 绛旀搴旇鏄A锛孖1>I2鍚с侷1>I2鍙互鍒嗘垚0-蟺/4锛屜/4-蟺/2鏉ョ湅锛岃繖涓ゆ鍒嗗瓙绉垎鐨勭粷瀵瑰煎ぇ灏忔槸鐩稿悓鐨勶紝鍓嶅崐娈垫鍚庡崐娈佃礋锛屼絾鍓嶅崐娈电殑鍒嗘瘝瑕佹瘮鍚庡崐娈靛皬銆傛墍浠ョ浉鍑忓悗涓姝ｅ硷紝涔熷氨鏄疘1>I2銆
绛旓細f(x)=y=sinx-cosx=鏍瑰彿2*sin(X-鍏锛4锛.f(x)涓绛変簬f(-x)涓攆(-x)涓嶇瓑浜-f(x),鎵浠涓闈炲闈炲伓
绛旓細x + 蟺/2) 鎴 sinx = cos(x - 蟺/2)銆傚彟澶栦竴涓父鐢ㄧ殑鍏崇郴鏄敱鍕捐偂瀹氱悊鑰屾潵鐨勶細 sin²x + cos²x = 1銆 绉垎鍜屽井鍒嗘硶鍒欎篃甯稿父鐢ㄤ簬灏 sinx 鍜 cosx 浜掔浉杞寲锛屽湪寰Н鍒嗕腑锛屽sinx姹傚寰楀埌cosx锛屽cosx姹傚寰楀埌-sinx銆備互涓婂氨鏄竴浜涘熀鏈殑鍏充簬 sinx 鍜 cosx 涔嬮棿杞寲鐨勬柟寮忋
绛旓細cosx鍜sinx鐨勮浆鎹㈠叕寮涓锛歴inx=卤鈭氾紙1-cosx鈭2锛塩osx=卤鈭氾紙1-sinx鈭2锛夛紝sin锛埾锛2+x锛夛紳cosx锛宑os锛埾锛2+x锛夛紳鈥攕inx绛 璇佹槑锛歴inx鈭2+cosx鈭2=1锛岀Щ椤瑰緱锛歴inx鈭2=1-cosx鈭2锛屽紑骞虫柟寰梥inx=卤鈭氾紙1-cosx鈭2锛夈傚悓鐞唖inx鈭2+cosx鈭2=1锛岀Щ椤瑰緱cosx鈭2=1-sinx鈭2锛屽紑骞虫柟寰...
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绛旓細鎴戞潵琛ュ厖涓嬪惂锛岀敱浜巟鈭堬紙0锛屜锛夛紝閭ｄ箞sinx>0锛屽張sinx*cosx=3/8,鎵浠osx>0锛岄偅涔堝畠浠殑鍜屼笉涓鸿礋锛屽簲璇ヨ垗鍘
绛旓細sinx杞寲cosx鍏紡澶ц浆鍖栵細sin锛埾/2+伪锛=cos伪 cos锛埾/2+伪锛=-sinx 鎷撳睍锛氭鍒绛変簬浣欏鸡闄や互姝ｅ鸡锛屾寮︾殑骞虫柟鍔犱笂浣欏鸡鐨勫钩鏂圭瓑浜庝竴 涓夎鍑芥暟锛圱rigonometric Functions锛鏄鍩烘湰鍒濈瓑鍑芥暟涔嬩竴锛屾槸浠ヨ搴︼紙鏁板涓婃渶甯哥敤寮у害鍒讹紝涓嬪悓锛涓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囨垨鍏舵瘮鍊间负鍥犲彉閲忕殑鍑芥暟...
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绛旓細1銆sinx=卤鈭氾紙1-cosx鈭2锛塩osx 璇佹槑锛歴inx鈭2+cosx鈭2=1锛岀Щ椤瑰緱锛歴inx鈭2=1-cosx鈭2锛屽紑骞虫柟寰梥inx=卤鈭氾紙1-cosx鈭2锛夈2銆佹垨鑰卌osx=卤鈭氾紙1-sinx鈭2锛夎瘉鏄巗inx鈭2+cosx鈭2=1锛岀Щ椤瑰緱cosx鈭2=1-sinx鈭2锛屽紑骞虫柟寰梒osx=卤鈭氾紙1-sinx鈭2锛夈俿inx鍜宑osx鐨勫叧绯 1銆佸钩鏂瑰拰鍏崇郴锛坰in伪...
