8-10 对低含量气体吸收或解吸,由 dfrac (1)({k)_(y)}=dfrac (1)({k)_(y)}+dfrac (m)({k)_(x)} 出发,试
直线dfrac (x-1)(1)=dfrac (y)(2)=dfrac (z+3)(-2)-|||-__ __-|||-__与平面dfrac (x-1)(1)=
解方程。 dfrac (1)(2)x-5= dfrac (1)(2) 5y-2y=18 dfrac (1)(2)+x= dfrac (1)
直线dfrac (x-1)(2)=dfrac (y)(-1)=dfrac (z-2)(3)-|||-__与直线dfrac (x-1)(2)=dfrac (y)(
3、设 (x,y)=arctan dfrac (x)(y), 则 (1,1)=-|||-(A)1; (B)0; (C) dfrac {1)(2),dfrac
((y+dfrac {1)(2))}^2=dfrac (3)(4) D. ((y-dfrac {1)(2))}^2=dfrac (3)(4)
求直线dfrac (x-1)(1)=dfrac (y)(1)=dfrac (z-1)(-1)-|||-__ __在平面dfrac (x-1)(1)=dfrac
设函数 (x,y)=1-dfrac (cos sqrt {{x)^2+(y)^2}}(tan ({x)^2+(y)^2)} ,则当定设函数 (x,y)=1-df
过直线_(1):dfrac (x-1)(1)=dfrac (y-2)(0)=dfrac (z-3)(-1)-|||-__ __且平行于直线_(1):dfrac
(B) dfrac (x)(y)((y+1))^2-|||-(C) ^2((x+dfrac {1)(x))}^2. (D) dfrac (y)(x)((y+1)