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Let me think about this.  Let the radius of the wheel be r feet

1 revolution = 2pi*r feet

2 revolutions = 4pi*r feet

So the seat is moving at $$4\pi r$$ feet per minute.

with the $$\div$$ button

If you are doing calculations with mixed numerals it is best to put them in brackets like $$(3+1\div 2)$$

sounds good to me.

I hadn't finished my post - I got side tracked.  I must have published it unfinished. 

What she saves is a function of number of weeks, say it is n.

f(n) = 40+10.n where n is the number of weeks.

Now by definition of domain, it is all the possible values n can have. In this case it is non-negative integer. Since she might not save even for 1 week, we have to consider the case when n = 0.

Domain : set of all non-negative integers.

Range : 40+10.n where n is a non-negative integer.

I hope it helps.

$$^4C_0 = \frac{4!}{(4-0)!0!}=\frac{4!}{4!}=1$$

By definition, it is the coefficient of y to the power 0  in the expansion of (1+y)⁴ 

So if you do the expansion, the coeff. is 1.

Also, if you use the factorial formula and 0! being 1, the answer is 1.

You should know what y=cosx looks like

That is your starting point

$$y=4cos(n\theta)+1

the amplitude is 4

The period is 2\pi/n

\mbox{ The 1 on the end mean that the whole graph is raised 1 unit }

\mbox{ so instead of it being centred on the x axis (y=0) it is centred on y=1}$$

Chris, how are you entering attachments - are they straight off the net?

e is just a number   

$${{\mathtt{e}}}^{{\mathtt{1}}} = {\mathtt{2.718\: \!281\: \!828\: \!459\: \!045\: \!2}}$$

you do not need to know what e^8 is to work out e^3

just do it on a calculator.

You should look here

0! = 1 (By definition)

26P26 = 26!/(26-26)! = 26! This is how many ways you can order 26 items.

The answer is 26! ways.

If you are entering mixed numeral put them in brackets, for example

(2+3/4)-(9+7/8)

that's funny 

I have no idea about chemistry but I will assume DavidQD knows what he is talking about and tick the answer.

I assume that the answer is in cm2.

And that it is perpendicular height.

And that our anonymous friends answer is in cm.

Then yes, that is a good answer.  

This is an acid-base titration calculation.

HCl (known as hydrogen chloride in a gas state and as hydrochloric acid when dissolved in water), reacts with NaOH Sodium hydroxide (lye) with a molar titration ratio

of 1:1.

The gram molecular mass of NaOH is 39.99715g/mole. To find the moles of 0.80g of NaOH divide the known mass by the gram molecular mass of Sodium hydroxide.

Incidentally, the gram molecular mass of HCl is 36.4611g/mole.

Note that the molar ratios are 1 to 1, but the mass ratios are not.

~~D~~

add  $$\left(\frac{14}{2}\right)^2 = 49$$

find the 54th term of the sequence -8, -5, -2, . .

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The n^th term is given by:  

a_n = -8 + 3(n-1)

See if you can take it from there........

Try looking here.

Difference between combinations and permutations

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Combinations count sets of things

Permutations count arrangements within sets

For instance, in combinations, the set {1,2} is the same as set {2,1}. The set is counted once.

However, permutations view the two sets as completely different things. Thus, in permutations, {1,2} ≠ {2,1}.  

Don't forget the dollar sign!

My goodness Chris you so look for the long way sometimes!

Just do it with an ordinary division. You get 56 with 1 left over 

That's   $$56\frac{1}{4}$$

or on a calculator

$${\frac{{\mathtt{225}}}{{\mathtt{4}}}} = {\mathtt{56.25}}$$

what is the radius of circle that has a circumference of 56 ft?

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Mmmmm...... let's reject that last answer...it isn't correct......

We have that

C = 2*pi*r    where C is the circumference and r is the radius....for convenience, I'll use 3.14 for pi

So we have

56 = 2 * 3.14 * r

Divide both sides by  2 * 3.14  and we have

(56)/ (2 * 3.14) = r

8.91 = r       

You go to Egypt and follow the tourist trail.