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瞿姜宝104523、X=0.1010B,Y= - 0.0111B,求[X - Y]补=B - 上学吧普法考试
滑范倪13726919542 ______[答案] x+y=a x-y=b x=(a+b)/2 y=(a-b)/2 xy=(a+b)/2 * (a-b)/2=(a^2-b^2)/4=c ---------(1) a+b+c=50 c=50-a-b ------------------------------------------(2) a^2-b^2=4(50-a-b) a^2+4a-b^2+4b=200 a^2+4a+4-(b^2-4b+4)=200 (a+2)^2-(b-2)^2=200=225-25=15^2-5^2 a+2=15, a=...
瞿姜宝1045已知a/(x2 - yz)=b/(y2 - zx)=c/(x2 - xy) 求证ax+by+cz=(x+y+z)(a+b+c) 我要过程,那种看不懂的别抄过来 -
滑范倪13726919542 ______[答案] a/(x2-yz)=b/(y2-zx)=c/(x2-xy) = k (1) 利用合分比 (a+b+c) / (x^2+y^2+c^2-xy-yz-xz) = k (2) (1)左边分别在分子,分母乘以a,b,c得 ax/x^3-xyz=by/(y^3-xyz)=cz/(x^3-xyz) = k 利用合分比 =(ax+by+cz) / (x^3+y^3+z^3-3xyz) = k 由于x^3+y^3+z^3-3xyz = (x+y+z)...
瞿姜宝1045已知:a=xy+z,b=yz+x,c=zx+y,且x+y+z≠0,试求aa+1+bb+1+cc+1的值. -
滑范倪13726919542 ______[答案] ∵x+y+z≠0,把a= x y+z,b= y z+x,c= z x+y代入 a a+1+ b b+1+ c c+1得: = x x+y+z+ y x+y+z+ z x+y+z = x+y+z x+y+z, =1. 故答案为:1.
瞿姜宝1045因式分解(x+y)(x+y+2xy)+(xy+1)(xy - 1)已得出答案令x+y=a,xy=b,则原式=a(a+2b)+(b+1)(b - 1)=a^2+2ab+b^2 - 1=(a+b)^2 - 1=(a+b+1)(a+b - 1)故原式=(x+y+xy+... -
滑范倪13726919542 ______[答案] (x+y+xy+1)(x+y+xy-1) =(x+1)(y+1)(x+y+xy-1) 是因为 x+y+xy+1=x(y+1)+(y+1)=(x+1)(y+1) 这是分组分解法
瞿姜宝1045为什么xy系数是1?那XY+XY+XY的系数是多少那AB+CD+EF的系数是多少本人新初一,求详解, -
滑范倪13726919542 ______[答案] 系数说白了就是项前面的数字 xy=1·xy,系数是1 你可能是把系数和次数搞混了 计算前,xy+xy+xy有三项,每一项的系数都是1 计算后,xy+xy+xy=3xy,系数是3 ab+cd+ef有三项,每一项的系数都是1 不懂追问~
瞿姜宝1045分解因式:1、 - 14abc - 7ab+49ab²c 2、9a² - 四分之一b² 3、x²(x - y)+(y=x) 4、 -
滑范倪13726919542 ______ (1)-14abc-7ab+49ab²c=7*7abbc-2*7abc-7ab=7ab(7bc-2c-1)(2)9a²-1/4b²=(3a)²-(1/2b)²=(3a+1/2b)(3a-1/2b) (3)x²(x-y)+(y-x) =x²(x-y)-(x-y) =(x²-1)(x-y) =(x+1)(x-1)(x-y)(4)3ax²+6axy+3ay²=3a(x²+2xy+y²)=3a(x+y)²
瞿姜宝1045若实数a,b,c,满足2的a次方+2的b次方=2的(a+b)次方,2的a次方+2的b次方+2的c次方=2的(a+b+c)次方,求c的最大 -
滑范倪13726919542 ______ 2的a次方+2的b次方=2的(a+b)次方=2^a*2^b 2的a次方+2的b次方+2的c次方=2的(a+b+c)次方 =2^a*2^b*2^c 假设2^a=x,2^b=y,2^c=z x+y+z=xy+z,x+y+z=xyz xy+z=xyz z=xy/(xy-1)=1+1/(xy-1) 2^c=1+1/[(2^(a+b)-1] <+∞ 显然c没有最值
瞿姜宝1045请写出算式和答案1.(x+y - 2)(x+y+2) - (x - y - 2)(x - y+2)2.设x+Y=5,XY=3,求X3次+Y3次的值为?3.已知:9a2次+24a+12b2次 - 12b+3c2次 - 3c+19又3分之4=0,求9... -
滑范倪13726919542 ______[答案] 1、=(x+y)^2-4-[(x-y)^2-4] =(x+y)^2-4-(x-y)^2+4 =4xy 2、=(x+y)(x^2+y^2+xy) =5(x^2+y^2+3) =5[(x+y)^2-1] =5(5^2-1) =120