死肥老蕭

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[ 本帖最後由 死肥老蕭 於 2007-10-8 03:43 編輯 ]

請各位解答這問題： (大學 differential geometry)

for a sphere of any radius and any torus, show that

1/(2π) ． ∫∫sphereK=2

1/(2π) ． ∫∫torusK=0

神機．新手

1.If f(x)=x^2-2x-5, find the value of k such that f(k+1)=k.

2.A wire of 24m long is cut into two parts .Then they are bent to form two squares.
(a) Express the total area A of the squares formed in terms of x.

(b) Find the minimum value of A

好難...諗左好耐都諗唔到...幫幫手

1.              f(k+1)=k
     (k+1)^2-2(k+1)-5=k
                 k^2-k-6=0
               (k-3)(k+2)=0
               k=3ork= -2
2          let the waire cut to 4x cm and (24-4x) cm

a.        A=((24-4x)/4)^2+(4x/4)^2
             =(6-x)^2+x^2
             =2x^2-12x+36
b.        A=2x^2-12x+36
             =2(x^2-6x+3^2)+36-2(3^2)
             =2(x-3)^2+18
             so the min. value of A is 18 com^2

回應2#- -~
點識你果條- -
我integral都未學-_-

[ 本帖最後由 『小龍龍﹏ 於 2007-10-20 08:20 編輯 ]

神機．新手

勁...
多謝大大幫忙~~~
但係有少少唔係好明...

邊到5明呢-_-? ??

神機．新手

1.              f(k+1)=k
     (k+1)^2-2(k+1)-5=k
                 k^2-k-6=0
               (k-3)(k+2)=0
               k=3ork= -2
唔明點解可以飛到咁快...我今日補習問到點做...都唔止咁少行

-______________________________________-
那個你有f(x)嘛- -~跟住話f(k+1)=k
咪姐將k+1代落個function度- -~
咁咪變(k+1)^2-2(k+1)-5=k
之後再拆啦- -有幾快-_-
lie個答案拎哂分嫁la- -~

光劍滅殺

Why is the Bunsen burner a better device than a gas stove for heating a test tube and its contents in the laboratory ?


中2 IS..


邊個可以教我.."

囧。。
都冇人問ｇｅ ＂

無錢

有冇人可以幫我作篇「我最難忘的地方」

中2中文科

死肥老蕭

問功課,唔係請槍.....

乂光仔乂

你能夠回答死神那一條大學數學題嗎 ???

另回答"Why is the a better device than a gas stove for heating a test tube and its contents in the laboratory?"

Compare with a gas strove , the diameter of the throat hole of a Bunsen Burner is narrower than that of  gas stove. The flame given out from a gas stove is much weaker than a Bunsen Burner(around 180 degree celsius). Alternatively, with the opening of the air hole of a Bunsen burner, the temperature can increase at around 350 degree celsius. Your main objective is to heat the substance in a boiling tube(should not be test tube). In this situation, using a Bunsen burner takes the advantage that can heat the substance effectively in the laboratory. Therefore, Bunsen burner would be preferable.

[ 本帖最後由 乂光仔乂 於 2008-3-10 00:55 編輯 ]