【单选题】
电流从头部到身体任何部位及从左手经前胸到脚的途径是最危险的。
【单选题】
石油沥青的组分长期在大气中将会转化,其转化顺序是()。
【单选题】
<img class="kfformula" src="20190809/1565313651838733.png" data-latex="\sqrt {7}+\sqrt {3}"/>与<img class="kfformula" src="20190809/1565313651801618.png" data-latex="\sqrt {7}-\sqrt {3}"/>的等比中项是( )
①
<img class="kfformula" src="20190809/1565313651278262.png" data-latex="4"/>
②
<img class="kfformula" src="20190809/1565313651577788.png" data-latex="\pm 4"/>
③
<img class="kfformula" src="20190809/1565313651689008.png" data-latex="\pm 2"/>
④
<img class="kfformula" src="20190809/1565313651298877.png" data-latex="2"/>
【单选题】
等差数列0,-3,-6,······的通项公式是( )
①
<img src="20190809/1565314218197257.png" title="1565314218197257.png" alt="图片5.png"/>
②
<img src="20190809/1565314240415972.png" title="1565314240415972.png" alt="图片6.png"/>
③
<img src="20190809/1565314247141241.png" title="1565314247141241.png" alt="图片7.png"/>
④
<img src="20190809/1565314264699167.png" title="1565314264699167.png" alt="图片8.png"/>
【单选题】
下述结论正确的是( )
①
数列0.9,0.99,0.999,0.9999是无穷数列
【单选题】
等差数列<img class="kfformula" src="20190809/1565315219717157.png" data-latex="\left \{ {{a}_{n}} \right \} "/>首项<img class="kfformula" src="20190809/1565315219801596.png" data-latex="{a}_{1}=1"/>,公差<img class="kfformula" src="20190809/1565315219560191.png" data-latex="d=-3"/>,当<img class="kfformula" src="20190809/1565315219192999.png" data-latex="{a}_{n}=-56"/>时,项数<img class="kfformula" src="20190809/1565315219715609.png" data-latex="n"/>等于( )
【单选题】
在等差数列<img class="kfformula" src="20190809/1565316326247415.png" data-latex="\left \{ {{a}_{n}} \right \} "/>中,<img class="kfformula" src="20190809/1565316326513469.png" data-latex="{a}_{1}=2"/>,<img class="kfformula" src="20190809/1565316326731066.png" data-latex="d=-2"/>,则前十项的和为( )
【单选题】
在等比数列{an}中,a?=3,a?=6,则第6项是( )
【单选题】
若x+y=1,则x与y的等差中项是()
①
<img src="20190822/1566466219602205.png" title="1566466219602205.png" alt="图片3.png"/>
②
<img src="20190822/1566466227823753.png" title="1566466227823753.png" alt="图片4.png"/>
③
<img src="20190822/1566466134821449.png" title="1566466134821449.png" alt="图片1.png"/>
④
<img src="20190822/1566466168502672.png" title="1566466168502672.png" alt="图片2.png"/>