计算圆x^2 (y-5)^2=16绕x轴旋转一周而成的环体的体积

2x-{-3y+[3x-2(3x-y)]}=2x+3y-[3x-2(3x-y)]=2x+3y-3x+6x+2y=5x+5y当x=-1,y=-1/5时5x+5y=5*(-1)+5*(-1/5)=-5-1

(1)=(x-y)(x+1)(x-1)(2)=x(x^2+x+1/4x)=x(x+1/2)^2(3)=4x^2+4xy+y^2-x^2+4xy-4y^2=3x^2+8xy-3y^2=(3x-y)(x+

两个式子作差得到x=5带入得到y=23

首先由格林公式得∮Pdx+Qdy=∫∫(Q'(x)-P'(y))dxdy然后化为极坐标的形式积分就可以出来了!我也是新手,一些数学符号弄不出来,希望你能看懂,当然高数的内容还是要多看课本,仔细比较,多

3x+2=y和11x=y,得到x=1/4,y=11/4,5X+4=Y和7X+6=Y,得到X=-1,Y=-1代入9X+8=y,不成立,方程组无解..

(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3=-(x-y)^3[-(xy-5)/x^2(x-y)]/[(xy-5)/xy]=(x-y)^3(xy-5)xy/x^2(x-y)(x

解:化简得{21x-5y=-104①14x-3y=4②①x13得-273x-65y=-1352③②x5得70x-65y=4④④-③得x=4将x=4带入②中得y=4∴原方程组的解是{x=4y=4我也是刚

1/2x（x-y)^2-1/5y（x-y）=(x-y)[1/2(x-y)-1/5y]=(x-y)(1/2x-1/2y-1/5y)=(x-y)(12/x-7/10y)4444^2-4443^2=(444

x^2+y^2=5,xy=2(x+y)^2=x^2+y^2+2xy=5+2*2=9(x-y)^2=x^2+y^2-2xy=5-2*2=1∴（1）(x+y)^2=9（2）x-y=±1（3）x^4+y^4

用1、2式求出x与y的关系（用y表示x）,代入1、3式,可以求出y,也就可以求出x1、2式求得：20x=-6y,即：x=-3y/10代入1、3式,得到y=10/51,则x=-1/17

(-x-2y)*(3x-y)=-3x^2-5xy+2y^2

5(x+y)(x-y)-2(x+y)^2+3(x-y)^2=3(x-y)^2+5(x+y)(x-y)-2(x+y)^2=(3(x-y)-(x+y))(3(x-y)+2(x+y))=(2x-4y)(5x

(2x+y)(x+3y-1)=2x^2+6xy-2x+xy+3y^2-y=2x^2+7xy+3y^2-2x-y

3x-2y-5x+7y-1,其中x=-1/2,y=-1=-2x+5y-1=-2×(-1/2)+5×(-1)-1=1-5-1=-5;很高兴为您解答,skyhunter002为您答疑解惑如果本题有什么不明

=1/2x-1/(x+y)×[(x+y)/2x-(x+y)]=1/2x-1/2x+1=1/x+1=(x+1)/x

2x-6+y=7y=13-2x2x+y=1y=1-2xx+2y=5x=5-2yx-2y=7x=7+2y2x-3y=5x=(5+3y)/2x+y=15x=15-y2x-4y=6x=3+2y3x-2y=5

=((x+y)-(x-y))*((x+y)-3(x-y))=2y*(4y-2x)=4y*(2y-x)带入得到=4*-0.8*(-1.6-5)=4*0.8*6.6=21.12

2y=5x-3代入得3x-2(5x-3)=-1x=1y=1a=1/3b-12b-5/3b+5=1b=-12a=-52、把x=1y=3和x=2y=3分别代入方程3=k+b3=2k+bk=0b=33、把x

即xy=2²-(√3)=4-3=1原式=[(x+y)²-(x-y)²]/(x+y)(x-y)*[-(x²-y²)/x²y²]=(x

结果为1