搜搜考试网由X*2 3y*2=6Y
来源：学生作业帮助网 编辑：作业帮 时间：2024/06/05 19:04:35
第一题,这是个隐函数,两边对x求导得：2y'-1=(1-y')*ln(x-y)+(x-y)*(1-y')/(x-y)=(1-y')*ln(x-y)+(1-y')所以[3+ln(x-y)]y'=ln(x
y=5/2cos(1/2x+π/6)=5/2sin(π/2+1/2x+π/6)=5/2sin(1/2x+2π/3)方法1：y=sinx----->y=sin(x+2π/3)----->y=sin(1/
设x-y=mx+y=n则6m-2n=143m+n=5解得m=2n=-1即x-y=2x+y=-1解得x=1/2y=-3/2
由(1)得3x+3y+2x-2y=365x+y=36(3)由(2)得4x+4y-3x+3y=-20x+7y=-20(4)(3)×7-(4)得34x=272∴x=8把x=8代入(3)得y=-4∴x=8y
令x^2=y,代入到原式中即可.
{(x+y)/2+(x-y)/3=63(x+y)+2(x-y)=36(1)4(x+y)-3(x-y)=-20(2)由（1）*3+(2)*2得9(x+y)+6(x-y)+8(x+y)-6(x-y)=36
用x表示y3x-2y+6=0移项3x+6=2yy=3x/2+3当x=-2时代入y=3*-2/2+3=0
解方程：x=3,y=0;x+y=x-y=3;
x^2+3y^4+x+2y=1两边同时对x求导,得到：2x+3*4*y^3*dy/dx+1+2*dy/dx=0(12y^3+2)dy/dx=-1-2xdy/dx=-(1+2x)/(2+12y^3)
y=sinx先向左平移π/6,得y=sin(x+π/6)然后,纵坐标不变,横坐标变为原来的1/2,得y=sin(2x+π/6)最后,向上平移3/2,得y=sin(2x+π/6)+3/2
分别对y求导,求左边为1+【e^(x+y）×（dx/dy+1）】右边为2×dx/dy推的dx/dy：自己算下,没得草稿纸.
第二个方程是不是写错了2/（x+y）+3/（x-y）=6是这样吗
两边求微分：d(x^y+y^x)=d(f(x^2+y^2))对x^y可以这么看：先把X看成常数,对Y求微分相当于a^Y,再把Y看成常数对X求微分相当于X^a.那么就好用公式了如下：d(x^y）=X^Y
3(x+y)-4(x-y)=4(x+y)/2+(x-y)/6=1令a=x+y,b=x-y3a-4b=4(1)a/2+b/6=1则3a+b=6(2)(2)-(1)5b=2b=2/5a=(6-b)/3=2
若(x-y)/(x+y)=3那么x-y=3(x+y)x-y=3x+3y故x=-2y所以(x+2y)/(6x-7y)=(-2y+2y)/(6*(-2y)-7y)=0如果不懂,请Hi我,祝学习愉快!
2x-3y+z=0(1)3x-2y-6z=0(2)(1)*2-(2)*34x-6y+2z-9x+6y+18z=0-5x+20z=05x=20zx=4z(1)*3-(2)*26x-9y+3z-6x+4y
去括号：10Y+X-10X-Y=100X+Y-10Y-X9Y-9X=99X-9Y移向：18Y=108X解得：Y=6X
两边对x求导xy^2+sinx=e^yy^2+2xyy'+cosx=e^y*y'y'(e^y-2xy)=y^2+cosxy'=(y^2+cosx)/(e^y-2xy)
y=2xarctan(y/x)(y/x)'=(y'/x-y/x^2)(arctanu)'=1/(1+u^2)y'=2arctan(y/x)+2x*(y'/x-y/x^2)*[1/(1+(y/x)^2)