共50条信息
已知\(a=\dfrac{1}{\pi }\underset{2}{\overset{-2}{\int}}\,\left( \sqrt{4-{{x}^{2}}}+{\sin }x \right)dx\),则二项式\({{\left( \dfrac{x}{2}-\dfrac{a}{{{x}^{2}}} \right)}^{9}}\)的展开式中的常数项为 \((\) \()\)
已知等差数列\(\{a_{n}\}\)中,\(a_{5}+a_{7}=\int _{0}^{π}\sin xdx \),则\(a_{4}+a_{6}+a_{8}=(\) \()\)
若\({{\left( {{x}^{{2}}}-\dfrac{{1}}{ax} \right)}^{{9}}}(a\in R)\)展开式中\(x^{9}\)的系数是\(-\dfrac{{21}}{{2}}\),则\(\int_{0}^{a}{\sin xdx}\)等于 \((\) \()\)
若\(a{=}\int_{\frac{\pi}{2}}^{2}\sin{xdx}{,}b{=}\int_{0}^{1}\cos{xdx}\),则\(a\)与\(b\)的关系是\(({ })\)
\(\int_{e}^{a}{\dfrac{1}{x}}dx=3\),则\(a=\)( )
若由曲线\(y=x^{2}+1\),直线\(x+y=3\)以及两坐标轴的正半轴所围成的图形的面积为\(S\),则\(S=\) \((\) \()\)
\({\int }{{ }}_{0}^{\frac{\pi}{2}}\sin^{2}\dfrac{x}{2}dx{=}({ })\)
一物体在力\(F(x)=4x-1(\)单位:\(N)\)的作用下,沿着与力\(F(x)\)相同的方向从\(x=1\)运动到\(x=3\)处\((\)单位:\(m)\),则力\(F(x)\)所做的功为 ( )
物体以速度\(v(t)=3t^{2}-2t+3(m/s)\)做直线运动,它在时刻\(t=0(s)\)到\(t=3(s)\)这段时间内的位移是 \((\) \()\)
如图,阴影区域的边界是直线\(y=0\),\(x=2\),\(x=0\)及曲线\(y=3{x}^{2} \),则这个区域的面积是\((\) \()\)
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