一个边长是9.2m的正方形花坛,它的周长是多少米?面积是多少平方米? 理工学科数学
\u6570\u5b66 \u7406\u5de5\u5b66\u79d1 \u5b66\u4e60\u7528\u9006\u63a8\u6cd5\uff0c\u5148\u53bb\u5206\u6bcd\uff0c\u4e24\u8fb9\u540c\u4e584\uff081+x\uff09(1+y)(1+z),\u53c8\u56e0\u4e3ax+y+z=1\u5f974+12xzy+8zy+8xz+8xy<=6+3zy+3xy+3zx+6zxy
6zxy+5zy+5xz+5xy<=2
\u53c8\u56e0\u4e3ax,y,z\u662f\u6b63\u6570\uff0cx+y+z=1\u53ef\u77e5x,y,z\u90fd\u662f\u5c0f\u4e8e1\u5927\u4e8e0\u7684\u6570
\u6545xzy,zy,xz,xy\u90fd\u662f\u662f\u767e\u5206\u4f4d\uff0c\u5341\u5206\u4f4d\u7684\u5c0f\u6570,\u7531\u6b64\u53ef\u77e5
1<6zxy+5zy+5xz+5xy<=2
\u6ee1\u8db3\u6761\u4ef6\uff0c\u5373\u6210\u7acb\u3002
\u8fd8\u6709\u5176\u5b83\u7684\u65b9\u6cd5\uff0c\u4f60\u4e5f\u53ef\u4ee5\u8bd5\u7740\u53bb\u63a8\u6572\u3002
\u5965\u6570\u8001\u5e08\u5e2e\u4f60\u56de\u7b54\uff1a
\u8fd9\u662f\u4e00\u9053\u8ffd\u53ca\u95ee\u9898\uff0c\u8ffd\u53ca\u8def\u7a0b\u4e3a\uff1a200*3=600\u7c73\uff0c\u6240\u4ee5\u8ffd\u53ca\u65f6\u95f4\u4e3a\uff1a600/(250-200)=12\u5206\u949f\uff0c\u6240\u4ee5\u7532\u8dd1\u7684\u8def\u7a0b\u4e3a12*250=3000\u7c73\uff0c\u4e59\u7684\u8def\u7a0b\u4e3a200*12=2400\u7c73
\u56de\u7b54\u5b8c\u6bd5\uff0c\u6700\u540e\u795d\u4f60\u5b66\u4e60\u8fdb\u6b65\uff01
面积是9.2×9.2=84.64(平方米)
绛旓細涓鐧惧潡涓嶅銆7.9x9.2=72.68锛堝钩鏂圭背锛0.8x0.8x100=64锛堝钩鏂圭背锛64<72.68 绛旓細100鍧椾笉澶熴備箻娉曠殑璁＄畻娉曞垯锛氭暟浣嶅榻愶紝浠庡彸杈硅捣锛屼緷娆＄敤绗簩涓洜鏁版瘡浣嶄笂鐨勬暟鍘讳箻绗涓涓鍥犳暟锛屼箻鍒板摢涓浣嶏紝寰楁暟鐨勬湯灏惧氨鍜岀浜屼釜鍥犳暟鐨勫摢涓浣嶅榻愶紱浠绘剰涓や綅鏁板钩鏂瑰锛23脳23= 36脳36= 42脳42= 56脳56...
绛旓細9.2mX5.2m=47.84骞虫柟绫筹紝0.7mX0.7m=0.49骞虫柟绫炽47.84骞虫柟绫/0.49骞虫柟绫=97.633鍧椼100鍧楀浜嗐
绛旓細瀹=锛9.2梅2-1.4锛壝2 =3.2梅2 =1.6绫 闀=1.6+1.4=3绫 闈㈢Н=3脳1.6=4.8骞虫柟绫 鍔犳补浣犲彲浠ョ殑
绛旓細濡傛灉浣犻棶鐨勬槸澶氬皯鐡风爾鐨勮瘽锛岃绠楁柟寮忎负锛9.2*7.9*1.08锛堝垎鍒殑闀匡紝瀹姐備互鍙婃崯鑰楀硷級=78.5骞虫柟鐨勭摲鐮栥傛崲鎴愬潡鏁扮殑璇濈瓑浜庯細78.5/0.64=123鐗囧乏鍙炽傦紙涓嶅惈韪㈣剼绾匡級 甯﹁涪鑴氱嚎鐨勶紙10鍘樼背瀹界殑韪㈣剼绾跨敤鍦扮爾鍔犲伐锛夎锛氬姞宸6鐗囩摲鐮栥
绛旓細鍦ㄥ凡鐭ュ洓鏉杈归暱锛屾眰闈炲钩琛屽洓杈瑰舰鐨勯潰绉彧鑳芥眰杩戜技鍊硷紝鍏堕潰绉瓑涓ょ粍瀵硅竟涓嚎闀垮害鐨勪箻绉備緥濡:鈶犻潰绉=(9.2+5.22)/2脳(6+8.16)/2=51.0468骞虫柟绫炽傗憽闈㈢Н=(9.6+8.55)/2脳(7.6+7.2)/2=67.155骞虫柟绫炽傗憿闈㈢Н=8.85脳(3.3+3.5)/2=30.09骞虫柟绫炽
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绛旓細1. y^2+2y+7=6, y^+2y=-1.4y^2+8y-5=4(y^2+2y)-5.= 4*(-1)-5.=-9.2. C.(y-1)(y+1)(y^2+1)-(y^4+1)=(y^2-1)(y^2+1)-(y^4+1).=y^4-1-y^4-1.=-2.3.4. A 5. a-b=3.6. 10^m=5, 10^2m=5^2=25.10^3n=3^3=27.10^3n-10^...
绛旓細涓鐧惧潡鍦扮爾闈㈢Н鎬诲叡鏄0.8x0.8x100=64锛堝钩鏂圭背锛夛紝姣旇緝鍙緱涓嶅銆傞暱鏂瑰舰鐨勯潰绉=闀棵楀 1銆侀暱鏂瑰舰闀跨殑閭ｆ潯杈瑰彨闀匡紝鐭殑閭ｆ潯杈瑰彨瀹姐2銆佸拰姘村钩闈㈠洖鍚屾柟鍚戠殑鍙仛绛旈暱锛屽弽涔嬪氨鍙仛瀹姐傞暱鏂瑰舰鐨勯暱鍜屽鏄浉瀵圭殑锛岄暱鐨勪负闀匡紝鐭殑涓哄銆傝嫢S涓烘鏂瑰舰鐨勯潰绉紝a涓烘鏂瑰舰鐨杈归暱鍒欙細S=a²銆
