【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?
【简答题】10圆锥的体积课堂练习及课后作业:.doc
【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
【单选题】Have you heard _____ news? The price of _____ petrol is going up again! [ ]
【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°=______.