作业帮Y=AB AC BC化简
来源：学生作业帮助网 编辑：作业帮 时间：2024/07/02 18:58:20
移项、得1.5y=-3系数化为一、y=-2很简单的呀
原式=(9x²+24xy+16y²-4x²+y²-5x²+6xy-y²)÷(-2y)=(30xy+16y²)÷(-2y)=-15x
其次方程解设为e^(ax)代入有a^4+a^2+1=0=>a^2=e^(j2π/3）或e^(j4π/3）推出次方程的四个解为e^(jπ/3）e^(j2π/3）e^(j4π/3）e^(j5π/3）故原方
因为x≤y所以x–y≤0即|x–y|=-(x–y)=y–x所以x+y-|x-y|=x+y-(y–x)=2x
（根号y/根号x-根号y)-(根号y/根号x+根号y)=｛根号y（根号x+根号y）｝/（x-y）-｛根号y（根号x-根号y）｝/(x-y)=(y+y)/(x-y)因为x=2y所以原式=2y/y=2
sinx+cosx=√2*sin(x+π/4)sinx-cosx=√2*sin(x-π/4)再问：能在详细点吗？谢谢啦再答：就是利用sin(A+B)=sinAcosB+cosAsinB和sin(A-B
化简（x+y）+(2x+y/1*2)+(3x+y/2*3)+...+(9x+y/8*9),并求当x=2,y=9时的值（x+y）+(2x+y/1*2)+(3x+y/2*3)+...+(9x+y/8*9)
∵令y=xt,则y'=xt'+t代入原方程,得xt'+t=t/(t-1)==>xt'=(2t-t^2)/(t-1)==>(t-1)dt/(2t-t^2)=dx/x==>2dx/x+[1/t+1/(t-
令p=y'则y"=pdp/dy代入原式：pdp/dy+p=pydp/dy+1=ydp=(y-1)dy积分：p=(y-1)²/2+c1即dy/dx=(y-1)²/2+c12dy/[(
第一个是立方和所以f(y)=(5y)³+1³-5+20y²=125y³+20y²-4
原式=[(x-y)(x-y)+(x+y)(x-y)]/2x=(x-y)(x-y+x+y)/2x=(x-y)·2x/2x=x-y=3-1.5=1.5
2y''+y'-y=0特征方程：2r^2+r-1=0根为：-1,1/2y=C1e^(-x)+C2e^(x/2)
很显然六位数abacbc是不能被7,11,13整除的正如一楼所说：abacbc=101000a+10010b+101c这三个数没有什么必然的联系用特殊值法也可以说明例如414515,7,11,13都不
（2x^3y^3+x^4y^2+x^2y^4)^2-x^2y^2(x+y)^2=x^2y^2（x^2+2xy+y^2)-x^2y^2(x+y)^2=x^2y^2(x+y)^2-x^2y^2(x+y)^
(y^2-12)/y
(-y+1/2)-y＞2+（y+2/3）=>-3y>3=>y/y+1/+/2y-1/=1-y+1-2y=2-3y
(x+y)(x²+y²)/(x^4-y^4)=(x+y)(x²+y²)/(x²+y²)(x²-y²)=(x+y)/(x&
2（-2+1）－2/3（﹣2－1）－3（﹣2+1）＋2/3(﹣2－1)=1