【单选题】若一次函数y=ax+b(a 0)在R上是减函数,则a,b应满足
【简答题】若y=ax,y= 在(0,+∞)上都是减函数,则y=ax 2 +bx在(0,+∞)上是( )函数。(选填“增”或“减”)
【单选题】若y=ax与 y=- b x 在(0,+∞)上都是减函数,对函数y=ax 3 +bx的单调性描述正确的是( )
D.
在(-∞,0)上是增函数,在(0,+∞)上是减函数
【单选题】初孕妇,26岁,孕35周,定期产前检查,血压140/80mmHg(基础血压90/60mmHg)。浮肿(+),诉胎动减少,该患者应做的检查哪项没有必要
【单选题】初孕妇,26岁,孕35周,定期产前检查,血压140/80mmHg(基础血压90/61mmHg)。浮肿(+),诉胎动减少,下列处理不适当的是
【单选题】初孕妇 ,妊娠 37+2 周,基础血压不高。近 5 天 眼花,血压160/100mmHg(21.3/13.3kPa),尿蛋白(++),尿雌激素/肌酐值为11,胎心148次/分,此时如何处理最恰当
【单选题】The resistance of a conductor varies ____.
A.
directly as its length and inversely as its cross-sectional area
B.
inversely as its length and directly as its cross-sectional area
C.
directly as its length and directly as its cross-sectional area
D.
inversely as its length and inversely as its cross-sectional area
【单选题】初孕妇,妊娠37+2周,基础血压不高。近5天头痛、眼花,血压160/100mmHg(21.3/13.3kpa)蛋白(++),尿雌激素/肌酐值为11,胎心148次/分,此时如何处理最恰当
【简答题】设a,b,c∈R,有下列命题: ①若a>0,则f(x)=ax+b在R上是单调函数; ②若f(x)=ax+b在R上是单调函数,则a>0; ③若b 2 -4ac<0,则 a 3 +ab+c≠0; ④若a 3 +ab+c≠0,则b 2 -4ac<0. 其中,真命题的序号是______.
【简答题】若函数y=ax与y=- b x 在(0,+∞)上都是减函数,则函数y=ax 2 +bx在(0,+∞)上是单调递______函数.(填“增函数”或“减函数”)