计算: (−3x 2 )(−x 2 2x−1)=
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∵y=cos(x2-π3)的单调递减区间即为y=-cos(x2-π3)的单调递增区间,由2kπ≤x2-π3≤2kπ+π(k∈Z)得:2π3+4kπ≤x≤8π3+4kπ(k∈Z),∴函数y=-cos(x
再答:满意吗,亲,别忘了给好评哦再答:0.21再问:用竖式怎样算?再答:图片中有啊再问:谢谢您再答:不客气再问:嗯
(1/8)^3x(1/4)^3x2^6x2^12=2的(-9-6+6+12)次方=2的3次方=8
(1)原式=x(x+9)x(x+3)+(x+3)(x−3)(x+3)2=x+9x+3+x−3x+3=2(x+3)x+3=2;(2)原式=-x−2x−1÷x2−4x−1=-x−2x−1•x−1(x+2)
1/(x2-5x+6)-1/(4x-x2-3)-1/(3x-x2-2)=1/(x2-5x+6)+1/(x2-4x+3)+1/(x2-3x+2)=1/(x-2)(x-3)+1/(x-3)(x-1)+1/
2^5-5x2^4+10x2^3-10x2^2+5x2-1=(2-1)^5=1再问:有过程吗再答:晕,这是二项式的展开式啊,就这样:(a+b)^n=a^n+C(n,1)a^(n-1)b+C(n,2)a
∵x2-x-2=0,∴x2-x=2,∴x2−x+23(x2−x)2−1+3=2+234−1+3=233.故选A.
行列式展开=x1^3+x2^3+x3^3-3x1x2x3而x1^3+x2^3+x3^3-3x1x2x3=(x1+x2+x3)(x1^2+x2^2+x3^2-x1x2-x2x3-x3x1)(展开右边即得
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lim(x²-9)/(x²-2x-3)x趋近于3=lim(x+3)(x-3)/(x+1)(x-3)x趋近于3=lim(x+3)/(x+1)x趋近于3=(3+3)/(3+1)=3/2
5x(x2-3x-1)-x2(1-x)=5x^3-15x^2-5x-x^2+x^3=6x^3-16x^2-5x
原式=-x+2x2+5+4x2-3-6x=6x2-7x+2.
0-36-1/36-18-1/1812-1/4
3√5×2√10=(3×2)×(√5×√10)=6×√50=6×5√2=30√2
设x2-3x=y,则原方程可化为:y+3y=4.即:y+3y−4=0.故选A.
7.5X2.3+1.9X2.5+12.5X2.5=2.5×2.3+1.9×2.5+12.5×2.5=2.5×(2.3+1.9+12.5)=2.5×16.7=10×16.7×1/4=167/4
80.4x2.5=(80+0.4)x2.5=80x2.5+0.4x2.5=200+1=201
∵设x2+3x=y,∴原方程可化为y-20y=8,整理得y2-20=8y.故选:D.
原式=12xy+3x2-5xy-6xy-4x2,=xy-x2.