求当x=0时,y=xsin1 x的极限
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Dimax,yAsIntegerPrivateSubCommand1_Click()x=Text1.TextIfx>0Theny=4*x+1Else:y=3*x+1EndIfText2.Text=yE
∵y+2与x-3成反比例函数,∴y+2=kx−3,∵当x=2时,y=-3,∴k=(-3+2)×(2-3)=1,∴y+2=1x−3,y=1x−3-2.∴当x=0时y=-73.
为方便打字,我用m代替x对y的导数d/dy*(y-x-lnx)=01-m-m/x=0所以m=x/(1+x),事实上你先对y求x的导,再取倒数也可以,殊途同归y=1,x=1,所以m=0.5
x+y/x-y=1/2取倒数x-y/x+y=2所以x-y/x+y-2x+2y/x-y=x-y/x+y-2(x+y/x-y)=2-2×1/2=2-1=1
y'=p,y''=dp/dx,xp'+xp^2-p=0p'=(-xp^2+p)/x,p'-1/x*p=-p^2伯努利方程,换元求出p,再求y
原式=1/2×2x-y/x+y+2x-y/6x-3y=1/2+1/3=5/6
(2x-y)/(x+y)=3所以(x+y)/(2x-y)=1/3原式=1/2*(2x-y)/(x+y)+1/3*(x+y)/(2x-y)=3/2+1/9=29/18
当x=1时,y=0当x=-3时,y=0即x=1或-3是方程ax²+bx+c=0的两根即a(x-1)(x+3)=0即y=a(x-1)(x+3)=a(x²+2x-3)又当x=2时,y=
y=(x2+2x+5)/x=(x+2+5/x)≥2+2√(x*5/x)=2+2√5最小值=2+2√5
用等价无穷小替换和洛必达法则.原式=lim(x→0)(sinx-x)/x^3=lim(x→0)(cosx-1)/(3x^2)=lim(x→0)(-sinx)/(6x)=lim(x→0)(-cosx)/
均值不等式.y=x/2+x/2+4/(x^2)当x/2=x/2=4/x^2,即x=2时,y最小,为3.
y = 2x / (x^2 - 1)化为 y = 2 / (x - 1
y=-2x+52x=5-yx=(5-y)/2-2x+5>02-5>-2x>-53/2
题目应该少了条件,应附加X,Y是一次函数关系则k=(100-0)/(20-4)=25/4且k=25/4=(Y-0)/(5-4)得Y=25/4
2x-y\x+y=32x-y=3(x+y)2x-y=3x+3y3x-2x=-y-3yx=-4y2x-y/2x+2y+x+y/6x-3y=(-8y-y)/(-8y+2y)+(-4y+y)/(-24y-3
由三角函数的定义可知:|sin1x|<1,由函数极限的性质可知:limx→0x=0故有:limx→0xsin1x=0故选择:B.
y与2x+1成反正比=>y(2x+1)=k定值(1,2)代入=>2*3=k=6(0,y)代入=>y*1=6=>y=6...ansorA,B成反正比=>A1:A2=B2:B1=>2:y=(2*0+1):
原式=(x-y)/x/((x^2-2xy+y^2)/x)=(x-y)/x乘以(x/(x^2-2xy+y^2))=(x-y)/x乘以(x/(x-y)^2)=1/(x-y)当x=2008,y=2009原式
再答:6028再问:x和y呢?再答:再问:谢!赏!