若x>-1,求y=x2 4x 5 x 1
来源:学生作业帮助网 编辑:作业帮 时间:2024/05/10 07:15:43
x(x+y)(x-y)-x(x+y)²=x(x+y)[(x-y)-(x+y)]=x(x+y)(x-y-x-y)=-2xy(x+y)=-2×(-1/2)×1=1
由题意可知,y=9x/10,带入得:(1-9x/10x)9*(x/x-9x/10)10>>>>>(1-9/10)*9(1/1/10)10>>>>>>>1/10*9*10*10=90所以答案是90
x=4,y=0.5,x+y=4.5(与人家的做法一样……)(1)解题思路是以S3为基准,用S3表示出S1,S2,S4即可.在三角形BCD中有:S2/S3=DF/CF,故S2=(DF/CF)S3;同理,
lny=ln(1+x)/x1/yy'=[x/(x+1)-ln(1+x)]/x^2y'=y[x/(x+1)-ln(1+x)]/x^2=(1+x)^(1/x)[x/(x+1)-ln(1+x)]/x^2
因为x:y:z=3:4:5所以设x=3k,y=4k,z=5k(k≠0)(1)z/(x+y)=5k/(3k+4k)=5k/7k=5/7(2)x+y+z=63k+4k+5k=612k=6k=1/2x=3k
因为X-Y=1所以原式=x*1+y*(-1)+2013=x-y+2013=1+2013=2014
∵x+7y=y-3x∴x=−32y∴x2−y2x2+y2=94x2− y294x2+y2=513故答案为513
x(x+y)(x-y)-x(x+y)2=x(x+y)[(x-y)-(x+y)]=x(x+y)(-2y)=-2xy(x+y)=-2×(-1/2)×1=1再问:18p3q3-2pq再答:7(x-1)3-1
x^5+x^4y+x^4+x+y+1=0x^4(x+y+1)+x+y+1=0(x^4+1)(x+y+1)=0然后因为x^4+1不可能等于0所以只有x+y+1=0x+y+1=03x+2y=1这两个公式,
(1)已知x+y=6,x²-y²=5,x^2-y^2=(x+y)(x-y)=5x-y=5/(x+y)=5/6(2)若x+y=3,x²+y²=5(x+y)^2=3
若是y的10次,我也不必说了若是y的10阶导数1:1/(1+x)2:-(1+x)^(-2)3:2(1+x)^(-3)……10:9!(1+x)^(-9)
因为(x+y)=1所以(x+y)^2=x^2+2xy+y^2=1因为x^2+y^2=3所以2xy=1-3=-2xy=-1(x+y)(x^2+y^2)=x^3+y^3+xy^2+yx^2=x^3+y^3
x+y=1x-y=2(x+2y)(x-2y)-(2x-y)(-y-2x)=(x+2y)(x-2y)+(2x-y)(y+2x)=x²-4y²+4x²-y²=5x&
7y(x-3y)²-2(3y-x)³=7y(x-3y)²+2(x-3y)³=(x-3y)²[7y+2(x-3y)=(x-3y)²(7y+2X
4x=9yx=9/4*y(1)(x+y)/y=[(9/4)y+y]/y=(9/4+1)y/y=9/4+1=13/4(2)(y-x)/2x=[y-(9/4)y]/[2*(9/4)y]=(1-9/4)y/
答案是:10把y替换成0.9x,代入后化简,可得(1/10)的九次方*10的十次方,结果是10.
x=1-2y∴x²+y²=4y²-4y+1+y²=5y²-4y+1=5(y-0.4)²+0.2所以最小值是0.2若x>0,y>0则1-2y>
∵|x+2y-1|+y²+4y+4=0∴|x+2y-1|+(y+2)²=0∴x=5,y=-2(2x-y)²-2(2x-y)(x+2y)+(x+2y)²=[(2x
1.x²+y²=625,x,y是正整数,故一个等于20,一个等于15,否则凑不出625.所以x+y=352.x*y=ax^y+b+1?,没理解错的话.a+b+1=969,8a+b+