All Answers 359230 Answers

Thanks for those great answers Chris and Heureka,

Heureka, I love the LaTex, I never would have thought to present it that way but it looks fabulous. :)

Notice that the first row = 4

And the next row has 8

And the next 12, etc.

So...we have

4(1) + 4(2) + 4(3) +..........+ 4(55)  =

4 [ 1 + 2 + 3+......+ 55]

And the sum in the brackets  is equal to ....    (55)(56)/2 = 1540

So,  4 times this =  6160

MathsGod1, please refer people to the sticky note on the right called "How do I type in fractions".  You should look at it yourself too.  

Hi Brittany :)

arc trig is the same thing use acos, asin and atan

I always think of things like that in this way :

(20 + 5) (20 + 5)

I see that multiplying the first two terms gives me 400

Then, I have 5 x 20,  twice  = 200

Finally, the last two terms multiplied together = 25

So..adding the results, we have......400 + 200 + 25 = 625

{However....since I just did this on "paper".....I guess it wasn't done in my head after all....!!! }

Hi Reinout.,

I like that rapid tables page. 

I have only used the rapid tables site a few times - maybe I should keep it in mind more :)

MathsGod1 your answer is an approximation.  It is probably not the answer required.

I expect the asker wants this answer simplified, not estimated.      

9 is the only Square number that goes into 27 so

$$\sqrt{27}=\sqrt9*\sqrt3 = 3\sqrt3$$

18,600,000,000,000 = 18 trillion, six hundred billion  ....  [at least in US terms ]

sin^-1(-1/2)  = 330°  or 11pi/12

[ This could also be a 30° angle in the 3rd quadrant  = 210°  or 7pi/6 ]

Yes that looks like a terrific answer Bertie.  I shall find time to study it.  :))

 7n+17=3n+76      subtract 3n, 17 from both side

4n = 59       divide both sides by 4

n = 59/4

The "normal" surface area would be

2*pi*r (r + h)

The "new" surface area would be

2*pi*(2r) (2r + 2h)=

2*pi*(2r)(2)(r + h)=

8*pi *r (r + h) =  4 times as great

Are you serious?

14^x=91

$$\small{\text{
$
\begin{array}{rcl}
14^x &=& 91 \quad | \quad \ln() \\
\ln(14^x) &=& \ln(91) \\
x\cdot \ln(14) &=& \ln(91) \\\\
x &=& \dfrac{\ln(91)} { \ln(14)} \\\\
x &=& \dfrac{4.51085950652} { 0.32220425047} \\\\
x &=& 1.70926923637
\end{array}
$
}}$$

$$14^{1.70926923637} = 91$$

or

$$\small{\text{
$
\begin{array}{rcl}
14\cdot x &=& 91 \\\\
x = \dfrac{91}{14} \\\\
x = 6.5
\end{array}
$
}}$$

$$14\cdot 6.5= 91$$

4%=0.04 so 0.5 is greater

e/3-3/4=7/12

e/3=16/12=4/3

e=4

5n=12

n=2.4

Thanks Brittany, that looks like a great answer.

Maybe mr. master means this

$$\\4a\times 5B+48+2\timesD7\times 67592a-92827D+4Z\\
$ you do times before plus$\\
$I started to answer this but really the meaning is terribly unclear$$$

On the net  the asterisk is a multiply sign     3 times 5 = 3*5

the x is just kept as a letter.

& has no meaning here at all.   

Can you present your question better so that we understand ?

square root of 40

you have to look for a square number that goes into 40

squared numbers are

1, 4, 9 ,16, 25, 36,49,  etc     do you understand where they come from?

1 is no help anyway and the only other one is 4.

$$\sqrt{40}=\sqrt{4\times 10}=\sqrt4\times \sqrt{10}=2\times \sqrt{10}=
2\sqrt{10}$$

Say you were asked to simplify $${\sqrt{{\mathtt{55}}}}$$

Well the only factors (besides 1 and itself) are  11 and 5

neither 11, nor 5 are square numbers.  There are no squar numbers that go into 55 so

$$\sqrt{55}$$     cannot be simplified. 

I hope that helps :)

My teacher taught us to guess and check.. 14*14=?*14=? until you get 91.