举一反三
- If X and Y are any two independent continuous random variables whose probability density is [img=41x25]1803dc1d154ea64.png[/img] and [img=38x26]1803dc1d1dd7772.png[/img],and whose distribution function is [img=47x25]1803dc1d26f6f50.png[/img] and [img=42x25]1803dc1d300d282.png[/img],then [img=47x25]1803dc1d26f6f50.png[/img] + [img=42x25]1803dc1d300d282.png[/img] must be the distribution function of a random variable.
- At what points (x, y, z) in space is the function continuous?[img=368x117]1803229635cda43.png[/img] A: [img=158x25]180322964081f92.png[/img] B: [img=159x25]180322964a26107.png[/img] C: [img=158x25]1803229654dadbb.png[/img] D: [img=80x25]180322965e5ca6a.png[/img]
- Given: function[img=34x25]17de81e321f7032.png[/img] has a second-order derivative within the interval of [img=8x19]17de81e32caa1a1.png[/img], and . Then, within the interval of , the curve is: A: increasing and convex upward B: decreasing and convex upward C: increasing and convex downward D: decreasing and convex downward
- 设随机变量X的概率密度[img=190x71]17de89917dd344e.png[/img]，则[img=87x47]17de89918b2d7b8.png[/img]的值为 A: 5 B: 3 C: 81/16 D: 4
- If [img=34x25]1803e254fa72e37.png[/img] is an even function and [img=33x25]1803e25502f5f78.png[/img] is an odd function，then ( ). A: All [img=191x25]1803e2550bd75da.png[/img] are even functions; B: All [img=191x25]1803e25513d5400.png[/img] are odd functions; C: [img=124x25]1803e2551c3ff9f.png[/img]are odd functions and [img=56x25]1803e25523e8c1c.png[/img]is an even function; D: [img=124x25]1803e2552c8c3c6.png[/img] are even functions and [img=56x25]1803e25534c2a44.png[/img] is an odd function.
内容
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下面代码的输出结果是[img=192x65]1803c8382772196.png[/img] A: 12 3 B: 81 3 C: 3 81 D: 3 12
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As [img=71x19]1803e23556504c2.png[/img], the function [img=104x25]1803e2356097b36.png[/img] is（ ）. A: an infinity B: an infinitesimal C: an unbounded function D: a bounded function
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The function [img=164x43]1803e256fccc749.png[/img] is a （ ）. A: bounded function B: periodic function C: even function D: odd function
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The function [img=170x29]1803e256de424b0.png[/img] is a composition function of [img=115x28]1803e256e701aae.png[/img] and [img=83x24]1803e256ef4fec1.png[/img].
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在环形区域[img=136x26]18030733be53638.png[/img]上， 绘制函数图形[img=129x27]18030733c6c9cd6.png[/img] A: Plot3D[x^2+y^2,{x,-2,2},{y,-2,2},Exclusions→Function[{x,y},0.5<x^2+y^2<2]] B: Plot3D[x^2+y^2,{x,-2,2},{y,-2,2},RegionFunction→Function[{x,y},0.5<x^2+y^2<2]] C: Plot3D[x^2+y^2,{x,-2,2},{y,-2,2},RegionFunction→Function[{x,y},2>x^2+y^2>0.5]] D: Plot3D[x^2+y^2,{y,-2,2},{x,-2,2},Exclusions→Function[{x,y},0.5<x^2+y^2<2]]