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Mainly used in the U.S., but something to do with forces and torque. Also, for calculating energy in bullets, too, apparently!

When placing the cursor over ERROR --22 --22 --20, I see:

Find the mean, median, and the mode of: 3,18,-22,-22,-20..so:

EDIT: Uh oh, I accidentally used 20 instead of -20!

EDIT 2: Updated!

What the heck is a foot pound?

I've just added this to the 'Puzzles' sticky thread.  Thanks

Mystery Number puzzle (8/8/14)

The mystery number has 3 digits is not divisable by 2 3 4 5 6 10

See solutions at:

Since this is function is periodic, there will be many maximums and minimums. We can find a couple and maybe make a general statement of where they will occur. Taking the derivative, we have:

1.5cos(pi*t/12)(pi/12) = 0

cos(pi*t/12) = 0

The first place that the cosine  = 0 is at pi/2. So, setting pi*t/12 = pi/2, we have that

t = 6

And the next place that the cosine = 0 is at 3pi/2...so

pi*t/12 = 3/2*pi

t = 18

Taking the second derivative, we have

-1.5(pi/12)sin(pi*t/12)(pi/12) =

[-1.5(pi/12)^2]sin(pi*t/12)

And when t = 6 , this is negative, so a maximum occurs at (6,6)

And when t = 18, the second derivative is positive, so this indicates a minimum at... (18, 3).

In general, a maximum depth of 6 m will occur every (6 ± 24t) (hrs??)  and a minimum depth of 3 m will occur every (18 ± 24t)(hrs??) where t is some integer.

Here's a graph of the function:

I could be wrong but I don't think that you can do this on the web2 calc.

You can do it on the WolframAlpha calc.

Look here.

Where did you get     $$t_{11}$$    from Alan?

I am completely lost. lol. 

Some things in life are meant to be a mystery.  Is this one on those?  

Ethan, I take it you are Australian.  May I ask where/what you are studying?  

I'm just curious, thanks. 

Ethan has asked some questions via private messaging.

But I will continue answering here.

First I need to try and explain the numbers that my conclusion is based on.

For both renting and buying this person began with $112,000

The rest, rent and repayments was paid for out of future earnings.

The figures below relate to what this person has after 3 years. (This in effect is what the original $112,000 has becomes.)

--------------------------------------

Renting: $112000 + interest on the term deposit - rent = $45,260

The amount has decreased because the cost of the weekly rent is more than the interest that is being earned on the term deposit. So this person has gone backwards he has less than he started with.

Renting Balance after 3 years = 131,060-85800= $45,260

---------------------------------------

Buying: This person will have some equity in his home.  If he sells it he can expact to 'realise' $168,923. The rest will go to the bank to finish the loan. However there have been some expenses along $12000 of expenses along the way so this will have to be deducted. (Just like the rent was deducted)

Buying Balance after 3 years = $168,923-$12000 = $156,923

So after three years if your rent then your saving of $112000 has reduced to $45,260

and if your buy then it has increased to $156,923

Is that a bit clearer now?

I think you sorted out the interest bit yourself?  And yes our answers should  be the same. 

Trata como esto:

***********Plug in t = 6 and t = 18 into the original function to find the depth maximum/minimum.************

sin^-1 is the same as arcsin or "asin" found on the calculator on the homepage.

Need more information to solve this question.

= 0.0041152263374486.

$$6+7=13\\
\mbox{But you already knew that
....i hope}$$

Now its clear ... thanx for all 

2*(10 x10) + (8 x 12) + (12 x 10) =

200 + 96 + 120 =

416 sq ft.

Thank you so much!

We can use similar triangles here:

(ht. of pole) / (ht. of pole shadow) = (ht. of building) / (ht. of building shadow)

(2.5 m) / (1.57 m) = (ht. of building) / (42.25 m)

Therefore...multiplyinh both sides by 42.25 m. we have

(42.25 m)*(2.5 m) / (1.57 m) = (ht. of building) ≈ 67.28 m = 67 m. (rounded)

Thank you! 

 sin3x =sin(x)*( 3cos^2 x - sin^2 x )

sin3x =

sin (2x + x) =

sin2xcosx + cos2xsinx =

(2sinxcosx)cosx + (cos^2x - sin^2x)sinx =

2sinxcos^2x + sinxcos^2x - sin^3x =

3sinxcos^2x - sin^3x =

sinx*(3cos^2x - sin^2x) ......and this equals the right hand side......