?

http://upload.lsforum.net/users/public/f12640Q18p1...

The figure shows a right circular cylinder with AC being a diameter of its upper face. AB and CD are two vertical lines on the curved surface. A curve is drawn as shown on the surface of the cylinder from B to C. If its shortest length is 6√(π^2 +1). Find the curved surface area of the cylinder.

Ans.: 24π cm^2

請問各位可詳細解釋中間的步驟嗎?

THZ!>,<

An equilateral triangle and a regular hexagon have equal perimeters.

If the area of the equilateral triangle is x.

Find the area of the regular hexagon.

Ans.: 1.5x

請問各位可詳細解釋中間的步驟嗎?

THZ!>,<

問題:7條直線及10個圓的最大交點數目。

答案是:7C2 + 2(10C2) + 2x7x10 = 251

但我5明點解會係咁解,請各位幫幫手詳細解答,thz!>,<"

已知圓形的式、centre和1個圓形外的點,求該圓形外的點連去圓形的式(2條tangent的式)。

請問這樣可以用咩方法計??

希望大家能解答我的問題,thz!=]

請問人大釋法一定能禁絕非香港居民的居留權?

會不會釋法後反而能讓外僱能獲得居港權?

請不要copy資料給我,thz!

0.49005n=0.99^n

請問呢題可以點解??

請詳細列出步驟,thz!=]

The y-intercepts of 2 parallel lines L and R are -1 and -3 respectively and the x-intercept of L is 3. P is a moving point in the rectangular coordinate plane such that the perpendicular distance from P to L is equal to the perpendicular distance from P to R. Denote the locus of P by T.

Describe the geometric relationship between T and L.

甚麼是perpendicular distance??

1) http://upload.lsforum.net/users/public/c3432Q32h19...

2) Let f(x) be a quadratic function. If the coordinates of the vertex of the graph of y=f(x) are (3,-4), which of the following must be true?

A. The roots of the equation f(x)=0 are integers.

B. The roots of the equation f(x)-3=0 are rational numbers.

C. The roots of the equation f(x)+4=0 are real numbers.

D. The roots of the equation f(x)+5=0 are nonreal numbers.

第1 and 2題答案是C及C,

請詳細列出步驟,THZ!=]

http://hk.news.yahoo.com/%E7%A7%9F%E7%AE%A1%E5%BE%...

看了新聞後,有點想不通,

政府若實行租金津貼,最大得益者為何不是租客,而是業主?

為甚麼業主更有理由向租客施壓大幅加租?

There is a rectangle with length 10cm and width 6cm, where all measurements are corrected to the nearest cm.

If the actual value of the perimeter is p cm, find the range of values of p.

Ans.:30<=p<34

Why the answer is not 30<=p<=34 ???

Please explain, thz!

Question:

http://upload.lsforum.net/users/public/p3218511dqu...

Ans:

http://upload.lsforum.net/users/public/z4160111dan...

請問點解個ans係咁?

沿x-axis rotate個3角形係360度??同埋係形成咩形狀??

請大家詳細講解一下,thz!=]

Lily is building towers of playing cards with more and more storeys.

http://upload.lsforum.net/users/public/h23905card1...

Find the difference between the number of cards in the n-storey card tower and the (n-1)-storey card tower.

Ans.:

http://upload.lsforum.net/users/public/t4643card2n...

我唔明點解係5+3(n-2)而不是5+3(n-1)...

希望大家能幫忙解釋一下,thz!

以下問題都已知答案,但我不明白為何是這些答案,

希望數學勁人幫幫忙,詳細解說一下,謝謝!>,<"

Q1)

http://upload.lsforum.net/users/public/w2876P290(Q...

ans. is C, but why B is not??

Q2)

http://upload.lsforum.net/users/public/z16858P302(...

ans. is A, but why B is not??

Q3)

Emily puts 6 pens into 3 different pencil cases.

In how many ways can she put the pens?

ans. is 729.

Q4)

8 boys and 5 girls are nominated for 4 different posts in a student association.

How many ways are there to select the students?

ans. is 17160.

Q5)

There are 8 bags on a table. 5 of them are empty and each of the other bags contains one ball in it. Andy puts a ball into a bag at random. If a bag is chosen afterwards, the probability of getting an empty bag is

ans. is 35/64.

Q6)

http://upload.lsforum.net/users/public/l20875P70(Q...

ans. is A.

Q7)

http://upload.lsforum.net/users/public/c30105P70(Q...

ans. is A.

Q8)

Which of the following figures cannot be used to tessellate a plane completely?

A. Parallelogram

B. Isosceles triangle

C. Regular hexagon

D. Regular pentagon

ans. is D.

Q9)

http://upload.lsforum.net/users/public/e9885P73(Q2...

ans. is D.

Q10)

http://upload.lsforum.net/users/public/w15768P128(...

ans. is C.

Q11)

In triangle ABC, the coordinates of the mid-points of the three sides are (1,5),(2,4) and (4,6) respectively. Which of the following points is a vertex of the triangle?

A. (-1,4)

B. (0,3)

C. (3,7)

D. (5,6)

ans. is C.

Q12)

http://upload.lsforum.net/users/public/i53040P189(...

ans. is D.

1) If the circumference of a circle is increased by 40%, then the area of the circle is increased by

ans.:96%

2) If z varies directly as x and inversely as y^2, which of the following must be constant?

ans.:x/(y^2)(z)

答案唔係應該分子分母調轉的嗎?

3) The coordinates of the points A and B are (1,-3) and (-5,7) respectively. If P is a point lying on the straight line y=x+2 such that AP=PB, then the coordinates of P are

ans.:(3,5)

4) Let O be the origin. If the coordinates of the points A and B are (18,-24) and (18,24) respectively, then the x-coordinates of the orthocentre of triangle OAB is

ans.:-14

不明白為何會是這個答案,請各位詳細列個步驟俾我呀,thz!>,<"

我有朋友佢要去ou-李家誠專業進修學院面試,佢之前報會計學HD是第1個課程選擇,而第2是旅遊與款待業HD,

那麼佢去面試ge時候應該穿西裝去嗎?

希望各位能解答我的問題,thz!=)

1) 我昨天見你的父親時，他正在工作。

2) 明天這個時候我正在與他在河邊散步。

3) 如果你明天中午來探訪我，我將正在吃午餐。

4) 明年今日我們將正在美國研究物理學。

5) 今晨你打電話給我時，我正與李小姐談話。

我的答案:

1) Your father had been working when I saw him.

2) I will have been taking a walk with him at this moment tomorrow.

3) I will have been having my lunch if you visit me at noon tomorrow.

4) We will have been reseraching physics in America one year later.

5) I had been talking with Miss Lee when you called me in the morning today.

標準答案:

1)When I saw your father yesterday, he was working.

2)I shall be taking a walk with him by the side of a river this time tomorrow.

3)I shall be having my lunch if you visit me at noon tomorrow.

4) We shall be studying physics in America this day next year.

5) I was talking with Miss Lee when you called me this morning.

我的答案和標準答案有出入,

但我不覺得自己的答案有錯,

請各位指點!!Thanks!!>,<"

There are 6 boys and 6 girls. How many ways are there to divide them into 6 groups with 1 boy and 1 girl in each group?

Ans.: 6!

I do not understand why this is the answer, please explain it to me, thanks!

Q：Consider a quadratic equation x²+(1-k)x+625=0. If the roots of the quadratic equation are negative, find the range of possible values of k.

答案個步驟點解係△≧0 ,, 而不是△>0 ??

(請加以解釋,,thz!=] )

我想問各位:由天水圍點樣去新蒲岡??

(港鐵既話要搭到邊個站,,之後要點樣行??)

(有冇巴士??)

以下問題我有答案,但係我想要詳細的步驟,答案必須是我所提供的。

① (cosθ+sinθ)²+(cosθ-sinθ)²

answer : 2

② 1/1-sinθ + 1/1+sinθ

answer : 2/cos²θ

③ (1-cosθ/1+sinθ) / (1-sinθ/1+cosθ)

answer : tan²θ

④ cosθ4次方 - sinθ4次方

answer : 1-2sin²θ

⑤ 開方1-cosθ / 開方1+cosθ

answer : 1-cosθ/sinθ

⑥

(a) 已知cosθ=開方3 / 2

tanθ=1 / 開方3

sinθ=1/2

而且cosθ=0.1

求1+ (sinθtanθ/cosθ)的值。

answer : 100

(b)已知tanθ=2 , 求(3sinθ-4cosθ)/(3sinθ+4cosθ)的值。

answer : 1/5