【简答题】显微镜的数值孔径值NA取决于物镜的镜口角(它的一半值为a)和玻片与镜头间的折射率n,可以表示为:NA= ( )*sin( ) 。
【判断题】咖啡树生长最理想的地质为半山和有树荫的森林中。 ()
【单选题】What is the average selling price of Sony Ericsson's phones in the 4th quarter of 2004?
【单选题】以怪石、奇松、云海、温泉四绝而闻名海内外的是
【简答题】We have received your letter of May 10th, (inform) us of the rise of the price.
【简答题】11圆锥体积的解决实际问题课堂练习及课后作业:.doc
【判断题】对外植体材料消毒的酒精浓度为 95% 。
【简答题】We have received your letter of May 10th, (inform) us of the rise of the price.A. informing
【简答题】因为sin30 0 = ,sin210 0 = - ,所以sin210 0 =sin(180 0 +30 0 )= -sin30 0 ; ;因为sin60 0 = ,sin240 0 = - ,所以sin240 0 =sin(180 0 +60 0 )= -sin60 0 ; 由此猜想、推理知一般地当 为锐角时,有sin(180 0 + )= -sin , ; 由此可知sin225 0 =
【简答题】计算:sin 2 1°+sin 2 2°+sin 2 3°+…+sin 2 88°+sin 2 89°+sin 2 90°=______.