初三数学求解，快快……急急……
\u521d\u4e09\u6570\u5b66\uff01\u5feb\u5feb\uff0c\u8c01\u80fd\u5e2e\u6211\u89e3\u7b54218949771\u521d\u4e2d\u65b0\u5efa\u804a\u5929\u4ea4\u53cb\u5b66\u4e60\u7fa4
\u8fde\u7ed3OE\uff0c\u5219OE\u5782\u76f4AC\u3002\u8bbeOE=OB=OD=R\u3002\u4e09\u89d2\u5f62ABC\u76f8\u4f3c\u4e09\u89d2\u5f62AOE\u3002
AB=6\uff0cBC=3\uff0cAO=6-R\u3002
AB/AO=OE/BC\uff0c6/(6-R)=3/R\uff0c\u89e3\u5f97\uff1aR=2\u3002
\u8bbe\u534a\u5706\u4e0eBC\u4ea4\u4e8e\u70b9F\uff0c\u8fde\u7ebfOF\u3002
\u5728\u4e09\u89d2\u5f62OBF\u4e2d\uff0cOB=OF\uff0c\u2220B=60\u00b0\uff0c\u6240\u4ee5\u4e3a\u6b63\u4e09\u89d2\u5f62\uff0c\u9762\u79ef=\u221a3\u3002
\u6247\u5f62ODF\u7684\u5706\u5fc3\u89d2\u4e3a120\u00b0\uff0c\u9762\u79ef=4\u03c0/3\u3002
\u6240\u6c42\u9634\u5f71\u90e8\u5206\u9762\u79ef=4\u03c0/3+\u221a3\u3002
绛旓細鈭燙DB=30搴︼紝CD鈯B锛岄槾褰遍儴鍒嗙殑2涓笁瑙掑舰涓2涓30搴60搴90搴︾殑鐩磋涓夎褰紝CD涓2鍊嶆牴鍙3锛岀洿瑙掍笁瑙掑舰鐨勯珮涓烘牴鍙3,2涓槾褰变笁瑙掑舰鍏ㄧ瓑銆傚張鍥犻槾褰辩洿瑙掍笁瑙掑舰涓30搴60搴90搴︾殑涓夎褰紝搴曢暱涓1锛屽垯闃村奖閮ㄥ垎闈㈢Н涓烘牴鍙3
绛旓細(1)瑙ｏ細璁緔涓巟鐨勫嚱鏁板叧绯诲紡涓猴細y=ax^2+bx+c 閭ｄ箞锛氬綋x=0鏃讹紝y=0;褰搙=130鏃讹紝y=130*90 褰搙=120鏃讹紝y=120*100 鍥犳鏈夊叧浜巃銆乥銆乧鐨勬柟绋嬬粍锛歝=0 130*90=(130^2)a+130b 120*100=(120^2)a+120b 瑙ｈ繖涓柟绋嬬粍寰楋細a=-1,b=220,c=0.鎵浠ワ細y涓巟鐨勫嚱鏁板叧绯诲紡涓簓=-x^2+22...
绛旓細1.2(x-3)^2=x^2-9 2(x-3)^2-(x+3)(x-3)=0 (x-3)(2x-6-x-3)=0 (x-3)(x-9)=0 x=3,x=9 2.(x-2)^2=(2x+3)^2 (x-2)^2-(2x+3)^2=0 [(x-2)+(2x+3)][(x-2)-(2x+3)]=0 (3x+1)(-x-5)=0 x=-1/3,x=-5 3.(x-2)(x-3)=12 x^2-...
绛旓細濡傚浘锛孉锛-1锛,6锛夋槸鍙屾洸绾縴=k/X(x<0)涓婁竴鐐癸紝p涓簓杞存鍗婅酱涓婁竴鐐癸紝灏咥缁昿鐐归嗘椂閽堟棆杞90掳鎭板ソ钀藉湪鍙屾洸绾垮彟涓鐐笲,姹俻鐐瑰潗鏍 灏咥(-1,6)浠ｅ叆鍑芥暟鏂圭▼寰楋細k=(-1)*6=-6锛涘洜涓篈鏄粫P鐐规棆杞埌B锛屾晠PA=PB锛孉PB=90掳锛堝嵆PA鈯B锛夛紱璁綪鐐瑰潗鏍囦负(0,m)锛屽洜A涓嶱鐐规按骞宠窛绂诲樊绛変簬B...
绛旓細瑙ｏ細1銆佺敱x-3<0, 寰梮<3 鐢 5(x-1)+6>4x寰 5x-5+6-4x>0寰梮>-1 鎵浠-1<x<3 2銆侊紙鍔犲噺娑堝厓娉曪級(1)寮-(2)寮忥紝寰 3y=3 鏈 y=1 浠ｅ叆(1)寮忥紝寰 x=3 3銆(1)寮+(2) 寮忥紝寰5x=5 鏈墄=1锛屼唬鍏 (2)寮忥紝寰梱=1銆
绛旓細瑙ｏ細锛1锛 涓ゆ牴涓 X1 = 1 X2 = 3 (2) y 闅 x 鐨勫澶ц屽噺灏 鐨 x 鐨勫彇鍊艰寖鍥翠负 x 锛 2銆傦紙3锛 灏辨槸璁╂眰 褰搙 涓轰綍鍊兼椂 鎶涚墿绾夸綅浜 x杞翠笂鏂广傛樉鐒 姝ゆ椂 x婊¤冻 1锛渪 锛3 锛4锛夊厛鑰冨療鏂圭▼ ax²+bx+c = 0锛屽畠鏈変袱鏍 1 鍜 3 鐢辨牴涓庣郴鏁扮殑鍏崇郴鐭ワ細1...
绛旓細鍥炵瓟锛2x^2-6x+x-3=-6 2x^2-5x+3=0 (2x-3)(x-1)=0 x1=3/2 x2=1
绛旓細鍥炵瓟锛2/333x1/2)=3銆傝D(X,y),鍒欏皬浜1澶т簬3;S涓夎褰BC=1/2xy=3;鎵浠=6/y;濡傛灉x 鏄暣鏁1,2,3甯﹀叆鍗冲彲,鍚﹀垯,鏈夋棤鏁扮偣銆
绛旓細璇佹槑锛氣埖寮D=寮C 鈭粹垹1=鈭3 鍦ㄥ渾O涓紝鈭3=鈭4 鈭粹垹1=鈭4 AB鏄洿寰勶紝鈭粹垹ADB=90掳 DE鈯B 鈭粹垹2=鈭4 鈭粹垹1=鈭2 鈭碅F=DF 鍙堚埖鈭6=鈭4+鈭5 鈭7=鈭1+鈭5 鈭粹垹6=鈭7 鈭碊F=FG 鈭碅F=FG
绛旓細瑙ｏ細璁剧敳鍗曠嫭瀹屾垚宸ヤ綔闇瑕亁澶╋紝鍒欎箼闇瑕亁+3澶┿傛牴鎹鎰忓彲浠ュ垪鍑哄涓嬬瓑寮忥細1-锛1/x +1/(x+3)锛*2=1/(x+3) * (x-2)瑙ｅ緱锛歺=3 (澶)鍒欙紝x+3=3+3=6(澶)鎵浠ワ紝鐢插崟鐙畬鎴愯繖椤瑰伐浣滈渶瑕3澶╋紝涔欓渶瑕6澶┿
