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# 問幾題微積分

因為微積分聽不懂，老師又派了作業

所以想請會的人解一下這幾題

find dx/dy in two ways:

(a)by implicit differentiation.

(b)dy differentiating an explicitformula for y.

1. x^2+y^3=12

2.x+1/y=5

find dx/dy by implicit differentiation.

1.y^2+3xy - 4x^2=9

2.(3x*y^2+1)^4=2x-3y

應用問題

1.The output of a certain plant is Q=0.06x^2+0.14xy+0.05y^2 units per

day,where "x" is the number of hours of skilled labor used and "y" is the

number of hours of un skilled labor used. currently, 60 hoursof skilled

labor and 300 hours of unskilled labor are used each day. use calculus to

estimate the change in un skilled labor that should be mad to offset a 1-hour

increase in skilled labor so that out put will be maintained at its current level.

2.when the price of a certain commodity is P dollars per unit, customers

demand "x" hundred units of a commodity, where x^2+3px+p^2=79

how fast is the demand x changing with respect to time when the price is

$5 per unit and is decreasing at the rate of 30 cents per month?

3.A circle oil slick spreads in such a way that its radius is increasing at the rate 20 ft/hr. How fast is the area of the slick changing when the radius

is 200 feet?

4.At a certain factory, output Q is related to inputs "u" and "v" by the

equation Q=3u^2+[(2u+3v)/(u+v)^2] If the current levels of input are

u=10 and v=25, use calculus to estimate the chang in input v that should

be mad to offset a decrease of 0.7 unit in input u so that output will be maintained at its current level.

麻煩各位解答時附上過程，我要看懂它到底是怎麼算的!謝謝!

對不起，他最多只能給20點而已，我也沒辦法...

題目就只有這樣而已阿

### 2 Answers

- 小惡魔Lv 51 decade agoFavorite Answer
這樣一題20點會不會太少......

2007-11-27 02:33:20 補充：

點數很少我先回答幾題

解法第一頁

http://www.wretch.cc/album/show.php?i=jiunyan0309&...

解法第二頁

http://www.wretch.cc/album/show.php?i=jiunyan0309&...

解法第三頁

http://www.wretch.cc/album/show.php?i=jiunyan0309&...

解法第四頁

http://www.wretch.cc/album/show.php?i=jiunyan0309&...

解法第五頁

http://www.wretch.cc/album/show.php?i=jiunyan0309&...

應用問題我會再來補充回答,剩下應用問題2.3.4

2007-11-27 02:39:41 補充：

你的應用題第三題題目只有這樣嗎....

2007-11-27 02:50:48 補充：

應用問題3的解答

2007-11-27 02:51:54 補充：

應用問題三的解答

http://www.wretch.cc/album/show.php?i=jiunyan0309&...

前一個沒補充上去

其他待續

2007-11-27 11:03:04 補充：

那以後可以分成兩個問題問阿

這樣很少耶

哈哈哈

2007-11-27 12:03:16 補充：

應用問題二的解答

http://www.wretch.cc/album/show.php?i=jiunyan0309&...

還剩下最後一題

2007-11-27 12:53:28 補充：

應用問題四的解答

http://www.wretch.cc/album/show.php?i=jiunyan0309&...

解答完囉

我也不知道有沒有解錯

因為我英文也不好

我是請朋友告訴我題義

再以自己對題義的了解去解題

希望對你有幫助

Source(s): 一個要考統研的數學系雙主修統計系的學生, 自己, 自己, 自己, 自己