All Answers 358098 Answers

xvxvxv said: 

"alan .. for Q 2 The answer in the model answer is A .. so the area in part D is positive !"

No! The question asks for net displacement not total distance travelled.  When the velocity is negative the player is moving in the opposite direction to when the velocity is positive, so he is reducing his displacement.  If the model answer is A then it is wrong!

(Total distance travelled would be 20m).

Let r = length of riding course, s = length of swimming course and n = length of running course.

Then s = 0.2r and n = s/5 = 0.2r/5 so total length = r + 0.2r + 0.2r/5 = 1.24r

This equals 62km so 1.24r = 62;  r = 62/1.24 or:

r = 50 km

s = 0.2r = 10km

n = s/5 = 2km

14 and 2/3 = 11/3

CPhill  ... for Q 3 

I answerd like this 

Why can't you do these yourself Natasza?

To find a mean you just add up all the numbers and divide by how many there are.  It is another word for average.

The others can be done either by formula or on your calculator.  I expect there are stat functions on the web2 calc but I will admit that I have not looked.

Now, what in particular would you like help with?

This is included in the sticky threads

Aziz, that would depend on what restrictions were imposed and on what you mean by 'meet'.

If they were 50 people all in the same class then the probability would be close to 1.  

sam gave 2/5 of his money to his wife and spend 1/2 of the remainder. If he had #300 left, how much money did he have at first?

Let the total be T

$$\\\frac{3}{10}\;of\;T=300\\
\frac{1}{10}\;of\;T=100\\
All\;of\;total=1000\\$$

Here's my brilliant response.

and 

$$\lim\limits_{b\to^-0}\frac{a}{b}=-\infty$$

Note for both this situations a is not equal to zero.

so if you approach 0 from above the answer tends to +infinty

and if you approach 0 from below the answer tends to -infinity

Which is a part of the logic explaining why anything divided by 0 is undefined.

CPhill ... for Q 1 the answer in the model answer is    A 35mph  !!  

alan .. for Q 2 The answer in the model answer is A .. so the area in part D is positive ! 

because we find area not integral ... right ! 

Well, you were taught wrong!

The correct responce is "Undefined"

IF you want more advance reasons search through the

Sticky Topics

I have posted some brilliant responses to the question. (Others have too, but they are not as brilliant as mine).

Your humble servant

You can ask CPhill, too. He is very versed on Zeros. Especially Roman Zeros.

For question 2) you need to find the area under the curve as distance is the integral of velocity with respect to time. The areas of each section are easy to find as they are comprised of triangles and rectangles.  The only point to note is that the last section will contribute a negative area.  (You should find B to be the answer)

If he originally had M then if he gave (2/5)M to his wife he would have (3/5)M left.  If he spent half of this he would have half of it left.  Half of (3/5)M is (3/10)M.  This is equal to #300, so

$$\frac{3}{10}M=#300\\M=\frac{10}{3}\times #300\\
M=#1000$$ 

If you can do C then D should be straightforward.  For E first divide through by t.

Mmm I just noticed that I did not use any logs 

$$\\e^{ix}=cosx+isinx\\\\
e^{i\frac{\pi}{2}}=cos\frac{\pi}{2}+isin\frac{\pi}{2}\\\\
e^{i\frac{\pi}{2}}=0+i\times 1\\\\
e^{i\frac{\pi}{2}}=i\\\\
\mbox{raise each side to the power of i}\\\\
\left(e^{i\frac{\pi}{2}}\right)^i=i^i\\\\
e^{i^2\frac{\pi}{2}}=i^i\\\\
e^{(-1)\frac{\pi}{2}}=i^i\\\\
e^{\frac{-\pi}{2}}=i^i\\\\
therefore\\
i^i=e^{\frac{-\pi}{2}} \\\\therefore\\
i^i \mbox{ is a real number }$$

$$x^2=x \times x$$

But other than that it can equal anything.  It would depend on the rest of the question.

This could be the formula for the area of a square.

If the side length is x then area = x squared units squared

This would be a formula 

$$$Area = x^2$\\\\
If the side length is 6 cm then x=6 and\\
$Area = 6^2 = 36cm^2$\\\\
If the side length is 4inches then x=4 and\\
$Area = 4^2 = 16inches^2$\\\\
etc\\
Do you get the idea on how this might be useful?$$

x^2 = ? [Need more information]

We are all from different counties and taxes are different everywhere.  Plus, in any given country there are a lot of different taxes and they all have different rates.  So you need to be more specific.

How much tax?

Seems like it would be so small...0% chance...!