函数Y=X三次方加ax平方加bx加二分之一在x等于一处有极小值负二则ab等于?
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X³+Y³=(X+Y)(X²-XY+Y²)
令2x平方加3x三次方加1为t,则y=cos三次方t令cost为a,则y=a的三次方.所以导数为3cos平方(2x平方加3x三次方加1)*{-sin(2x平方加3x三次方加1)}*(4x+9x的平方)
x^3y-2x^2y^2+xy^3=x^3y+2x^2y^2+xy^3-4x^2y^2=xy(x^2+2xy+y^2)-4x^2y^2=xy(x+y)^2-4x^2y^2=12×7×7-4×12×12
y=2^(-3+4x-x^2)=2^[-(x-2)^2+1)]当x≤2时,y随x的增大而增大,即单调递增区间为(-∞,2],值域为(1,2];当x>2时,y随x的增大而减小,即单调递减区间为(2,+∞
X2+Y2-4X-6Y+13=0X2-4X+4+Y2-6Y+9=0(X2-4X+4)+(Y2-6Y+9)=0(x-2)2 +(y-3)2=0所以,x-2=0 x=2y-
x³+x²y+xy²+y³=x²(x+y)+y²(x+y)=(x+y)(x²+y²)
y'=3x²-2xy'
已知A=x³+2y³-xy²,B=-y³+x³+2xy²,其中x等于1\3,y等于2A-B=(x³+2y³-xy
求导完是3(X+1)平方-3(y-1)平方—9要求极值就得是3(X+1)平方-3(y-1)平方—9=0所以必须使3(X+1)平方-3(y-1)平方=9即(X+1)平方-(y-1)平方=3比如X=1Y=
x+y=1则x^2+y^2+2xy=1因为x^2+y^2=3则xy=-1x^3+y^3=(x+y)(x^2-xy+y^2)=1*(3+1)=4
先分解因式,后乘法.(X^4-Y^4)/(X^3+X^2Y+XY^2+Y^3)=(X-Y)(X+Y)(X^2+Y^2)/(X^3+X^2Y+XY^2+Y^3)=(X-Y)(X^3+X^2Y+XY^2+
f(x)=x^3+ax^+bx+a^在x=1处有极值10,显然,有f(1)=10成立,即:f(1)=1+a+b+a^=10a^+a+b=9①对f(x)求x的一阶导:f'(x)=3x^+2ax+b显然,
已知ax^3+ax²-4x^3+2x²+x+1=(a-4)x^3+(a+2)x²+x+1是关于x的二次多项式所以a-4=0即a=4所以a²+1/a²=
f(x)=4x*x*x+ax*x+bx+5;f'(x)=12x*x+2ax+bf'(1)=-12;f(1)=-12;4+a+b+5=-12;12+2a+b=-12;解得:a=-3,b=-18
f(x)=4x³+ax²+bx+5求导f'(x)=12x²+2ax+b带入x=1得f'(1)=12+2a+b=12f(1)=4+a+b+5=12得a=-3b=6f(x)=
y=x^3/3-(a+1)x^2+4ax+by'=x^2-2(a+1)x+4ay'=(x-2a)(x-2)当a>1时x>2a或x0(x≠2))函数单调增当a2或x
y=x^3-ax^2+1y'=3x^2-2ax令y'=0得x=0,x=2a/3y'在(0,2a/3)上y'
x³-y³-x²y+xy²=(x³-y³)-(x²y-xy²)=(x-y)(x²+xy+y²)-xy
(x+y)(x^2-xy+y^2)