作者dreamenjoy (今天也很爽)
看板Math
标题[微积] 几题~~~~
时间Thu Jun 9 00:02:34 2011
1.
S is the region formed by x=y,x+y-3=0 and x=0.please find the
double integral of ∫∫(2x+2y-1)dxdy
2.
The weekly cost to produce x widgets is given by
C(x)=75000+100x-0.03x^2+0.000004x^3,
0<=x<=10000 and the demand function for the widgets is given by
p(x)=200-0.005x,0<=x<=10000 Assume that the company sells exascly what
they protuce.
(a)What are the marginal cost,marginal revenue and marginal profit when 2500
widgets are sold?
(b)What are the marginal cost,marginal revenue and marginal profit when 7500
widgets are sold?
4.
使用Lagrange求点(1.2.4)至平面2x-3y+z=4之最短距离
2 √4-y^2 √4-x^2-y^2
5.∫ ∫ ∫ z√x^2+y^2+z^2 dzdxdy
0 0 0
6.Find dy/dx if x^y-y^x=0
麻烦各位了 感恩
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