【单选题】
计算1<img class="kfformula" src="20200624/1592991783289559.png" data-latex="{mo1SO}^{2-}_{4}" width="90" height="34"/>中含有的O的物质的量是( )mol。
【判断题】
如果矩阵<img width=16 height=18 src=https://main.ahjxjy.cn/design/html/js/vender/ueditor/themes/default/images/spacer.gif word_img=file:///C:/temp/msohtmlclip1/01/clip_image002.gif style=background:url(https://main.ahjxjy.cn/design/html/js/vender/ueditor/themes/default/images/word.gif) no-repeat center center;border:1px solid #ddd/>是非退化的,那么它一定是可逆矩阵.
【判断题】
两个零多项式的最大公因式是<img width=16 height=19 src=https://main.ahjxjy.cn/design/html/js/vender/ueditor/themes/default/images/spacer.gif word_img=file:///C:/temp/msohtmlclip1/01/clip_image002.gif style=background:url(https://main.ahjxjy.cn/design/html/js/vender/ueditor/themes/default/images/word.gif) no-repeat center center;border:1px solid #ddd/>
【单选题】
将0.lmol·<img class="kfformula" src="20200629/1593409309479184.png" data-latex="{L}^{-1}" width="46" height="31"/>醋酸溶液加水稀释,下列说法正确的是()。
①
溶液中c(<img class="kfformula" src="20200629/1593409309358634.png" data-latex="{H}^{+}" width="36" height="32"/>)和c(<img class="kfformula" src="20200629/1593409309469275.png" data-latex="{OH}^{-}" width="55" height="27"/>)都减小
②
溶液中c(<img class="kfformula" src="20200629/1593409309586142.png" data-latex="{H}^{+}" width="45" height="26"/>)增大
【单选题】
计算1mol<img class="kfformula" src="20200708/1594170134131282.png" data-latex="{O}_{2}" width="50" height="37"/>的质量是( )g。
【单选题】
“ <img width="19" height="17" style="background: url(/project/js/ueditor/themes/default/images/word.gif) no-repeat center; border: 1px solid rgb(221, 221, 221);" src="/project/js/ueditor/themes/default/images/spacer.gif" word_img="file:///C:/Users/t410i/AppData/Local/Temp/msohtmlclip1/01/clip_image002.jpg"/>”是哪种装饰音的符号 ( )
【单选题】
设<img class=jc-formula data-tex={ X }_{ 1 },\cdots ,{ X }_{ n } src=https://huaweicloudobs.ahjxjy.cn/8159F7186DE77C735294288BB1F8C1F1.png style=vertical-align: middle;/>是来自总体<img class=jc-formula data-tex=X src=https://huaweicloudobs.ahjxjy.cn/18E2773B1E2835B209E7E51B85285E80.png style=vertical-align: middle;/>的样本,且<img class=jc-formula data-tex=EX=\mu src=https://huaweicloudobs.ahjxjy.cn/39618736AA44811087C44938D156DBC3.png style=vertical-align: middle;/>,则下列是<img class=jc-formula data-tex=\mu src=https://huaweicloudobs.ahjxjy.cn/44B6A27E434C1345C3CEEB7A5249665D.png style=vertical-align: middle;/>的无偏估计的是
①
<img class=jc-formula data-tex=\frac { 1 }{ n } \sum _{ i=1 }^{ n-1 }{ { X }_{ i } } src=https://huaweicloudobs.ahjxjy.cn/C47B85208815D85D3DD90DFEC473F7FF.png style=vertical-align: middle;/>
②
<img class=jc-formula data-tex=\frac { 1 }{ n-1 } \sum _{ i=1 }^{ n }{ { X }_{ i } } src=https://huaweicloudobs.ahjxjy.cn/F592094A4BE03E45216F0FE940311E37.png style=vertical-align: middle;/>
③
<img class=jc-formula data-tex=\frac { 1 }{ n } \sum _{ i=2 }^{ n }{ { X }_{ i } } src=https://huaweicloudobs.ahjxjy.cn/72F0F6F417A0E32959CC0BA9BC395311.png style=vertical-align: middle;/>
④
<img class=jc-formula data-tex=\frac { 1 }{ n-1 } \sum _{ i=1 }^{ n-1 }{ { X }_{ i } } src=https://huaweicloudobs.ahjxjy.cn/1C176141AB6A855E8CFD52AEF5D595C0.png style=vertical-align: middle;/>
【单选题】
已知<img class="kfformula" src="20190809/1565317530438878.png" data-latex="a,b,c"/>是公比为2的等比数列,则<img class="kfformula" src="20190809/1565317530533557.png" data-latex="\frac {{b}^{2}} {ac}" width="74" height="64"/>等于( )
①
<img class="kfformula" src="20190809/1565317530127108.png" data-latex="\frac {1} {2}"/>
②
<img class="kfformula" src="20190809/1565317530414229.png" data-latex="1"/>
③
<img class="kfformula" src="20190809/1565317530771921.png" data-latex="\frac {1} {8}"/>
④
<img class="kfformula" src="20190809/1565317530451678.png" data-latex="\frac {1} {4}"/>
【单选题】
正五棱锥的底面积是<img class="kfformula" src="20190809/1565328530277328.png" data-latex="26{cm}^{2}"/>,高是<img class="kfformula" src="20190809/1565328530106797.png" data-latex="6cm"/>,则其体积是( )。
①
<img class="kfformula" src="20190809/1565328531591499.png" data-latex="104{cm}^{3}"/>
②
<img class="kfformula" src="20190809/1565328531884474.png" data-latex="{52cm}^{3}"/>
③
<img class="kfformula" src="20190809/1565328531242148.png" data-latex="78{cm}^{3}"/>
④
<img class="kfformula" src="20190809/1565328531496628.png" data-latex="156{cm}^{3}"/>
【单选题】
通过阻断<img class="kfformula" src="20200409/1586408554112324.png" data-latex="{\propto }_{1}"/>和 β 受体而发挥抗高血压作用的药物是()。