Equalities that satisfies equation 1: x ≤ -1/2 or x ≥ 3

Equalities that satisfies equatoin 2: x > -1 , x < 5

Draw a number line, find the overlapping region. There you go.

Answer: -1 < x ≤ -1/2, 3 ≤ x < 5

P.S. I visualized everything in my mind without using pencil or papers something could be wrong somewhere

Wrong concept. First, Charles's Law does NOT apply here. When Ice turns into liquid there's a decrease in volume.

You cannot use charles's law when there involve a change of state in between like liquid > ice.

General Knowledge:
1) When water turn into ice, there's an increase in volume.
2) Hence, a decrease in density. (P.S. refer Bio form4 textbook chapter 4)

Haven't you all done a question about a floating ice cube on water(with part of it above water surface)? when the ice cube melts, water level will still remains the same. This is because liquid have higher density + lower volume than the same mass of ice.

Refering to the question above, I have no idea why this happens unless youre heating the water well above 0 degree (say like heating it until 80). Then the answer is possible.

Btw, did I ever mentioned? I am a SPM student as well

2sin (x - 45) = 1

sin (x - 45) = 1/2

(x - 45) = sin^-1 1/2

x - 45 = 30, 150 (Range is -45< (x - 45) < 315)

x = 75, 195

This post has been edited by zeeyang: Nov 20 2010, 08:26 PM

Hah 40/40. Guys I don't understand how you could get 39. Don't you know that there would be 10 A, B, C, D respectively? There's 1 question I was unsure of but I know the answer straight away by the even distribution of ABCD

Memorizing is the BEST way to study maths. Proof: -

Several scientists were all posed the following question: "What is 2 * 2 ?"

The engineer whips out his slide rule (it's so old) and shuffles it back and forth, and finally announces "3.99".

The physicist consults his technical references, sets up the problem on his computer, and announces "it lies between 3.98 and 4.02".

The mathematician cogitates for a while, then announces: "I don't know what the answer is, but I can tell you, an answer exists!".

Philosopher smiles: "But what do you mean by 2 * 2 ?"

Logician replies: "Please define 2 * 2 more precisely."

The sociologist: "I don't know, but is was nice talking about it".

Behavioral Ecologist: "A polygamous mating system".

Medical Student : "4"

All others are looking astonished : "How did you know ??"

Medical Student : "I memorized it."


Just for a small laugh to ease tension