已知y1=x,y2=x² bx c
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(1)根据题意,可这样设:y1=k1xy2=k2/x(k1,k2为常数)(2)y=y1+y2=k1x+k2/x将x=1,y=-3;x=2,y=0代入y,得k1+k2=-32k1+k2/2=0联立解得k
解-2(X+1)/3+(X-5)/6=20-4(X+1)+X-5=120-4X-4+X-5=120-3X=129X=-43
解y2=2/y1=2/2x=1/xy2=2/y2=2/(1/x)=2xy3=2/y2=2/2x=1/xy4=2/y3=2/(1/x)=2x.不难发现yn是周期为2的数列y2006=y2=1/xy1*y
y1>y2-x+3>3x-4-x-3x>-4-3-4x>-7x所以当xy2
y1=k1x^2y2=k2/xy=k1x^2-k2/xk1-k2=3k1+k2=72k1=10k1=5k2=2y=5x^2-2/xx=3y=45-2/3=133/3
y1与x二次方成反比例y1=a/x^2y2与x+2成正比例y2=b(x+2)y=y1-y2=a/x^2-b(x+2)根据题意得:9=a-b(1+2)5=a-b(-1+2)解之得:a=3,b=-2y与x
y1=y2-2/3x+1=x2/3x+x=15/3x=1x=3/5y1=y2-5-2/3x+1=x-52/3x+x=1+55/3x=6x=18/5
(1)根据题意得:-23x+1=x,去分母得:-2x+3=3x,移项合并得:5x=3,解得:x=35;(2)根据题意得:-23x+1=x-4,去分母得:-2x+3=3x-12,移项合并得:5x=15,
y1>y2-x+3>3x-44x
由题意,不妨设:y1=k*根号x,y2=m/x²那么:y=y1+y2=k*根号x+m/x²已知当x=1时,y=-12;当x=4时,y=7,则有:{k+m=-12(1){2k+m/1
由y1-y2=x^2-2x-3=(x-3)(x+1),得1)当x>3orxy22)当-1
设y1=k1x−1,y2=k2x+2,∴y=k1x−1+k2x+2,把x=1,y=1;x=2,y=1,别代入上式得1=k231=k1+k24,(1分)解之得k1=14,k2=3,(2分)∴y=14x−
解由当x=2时,y1+y2=-1得2k1+2k2=-1即k1+k2=-1/2.①当x=3时,y1-y2=12得3k1-3k2=12即k1-k2=4.②由(1)与(2)联立解得k1=7/4,k2=-9/
先看看行不x=-100:.1:100;y1=f(x);y2=g(x);plot(y1,y2);
y1=-x+3,y2=3x-5因为y1>y2所以-x+3>3x-54x
当y1>y2时,2x-6>-5x+1,即7x>7,解得:x>1,因此当x>1时,y1>y2.
1.y1=y2:-x+2=3x+4=>4x=-2=>x=-1/2y1-1/2y1>y2:-x+2>3x+4=>xx=1y=1带入y=ax+7=>a=-6
y1=2x-1y2=5x+7y1=y2,2x-1=5x+7,x=-8/3y1与y2互为相反数,y1=-y2,2x-1=-(5x+7),x=-6/7y1比y2小,2x-1-8/3
x-2=3(2x-3)x-2=6x-96x-x=-2+95x=7x=1.4
若y1=y2那么a^(2x-7)=a^(4x-1)∴2x-7=4x-1解得:x=-3∴x=-3时,y1=y2若y1>y2那么a^(2x-7)>a^(4x-1)当a>1时,y=a^x为增函数∴2x-7>