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No  problem

Thanks....i appreciate that  !!1

Thank You CPhill! Oh Yea congrats on you being here for 4 years! We all appreciate you on here!

Ah thank you, forgive my ignorance!

Derivative is   2x +3

Yep....you got it ! 

4.

The height after the nth bounce is  given by :

8  * ( .80 )ⁿ

So.....after the 3rd bounce we have

8 * (.80) ³  =   4.1  ft

5. The bacterium increases by 24  every hour......so the function is

a_n  =  24n

Thanks!

percent error = l measured value - true value l  / true value x 100%  =

l 24  - 30 l  /  30  x 100%  =

l 6  l  / 30  x 100%  =

(6/30) x 100%  =

(1/5) x 100%  =

100% / 5  =

20%

The last one is correct

Omi  answered the second one in your earlier post

For the first  one

1:  A square and an equilateral triangle have equal perimeters. The area of the triangle is 2 sqrt 3 square inches. What is the number of inches in the length of the diagonal of the square?

Area  of triangle  is given by

2sqrt (3)  =  (1/2) side^2  * sin (60)

2 sqrt (3)  =  (1/2)side^2  * sqrt (3) / 2       simplify

2  = side^2 / 4

8  = side^2

√8  = side

So....the perimeter of the triangle   = 3√8  in

So.......the  side of the square  =  1/4  of this   =  (3/4)√8  in

And the diagonal  is √2  of this  =  √2 *  (3/4) √8  =   (3/4) * √16  in  =

(3/4)* 4   =    3 in

True: But w/o seeing the graph how would you know that at 3 months it's at its maximum population?

Wouldn't you just sub 3 for for t in your given function? Try it:

P(3) =4*3 + (100*3 / 3^2+400) + 500

P(3) = 12 +  (300 / 409) + 500

P(3) = 12 +  0.733496...  + 500

P(3) = 512.733486......

Congratulations!

She is German, and in Germany they use "," instead of "." for decimal point that we use in the English-speaking countries. So, in Germany, and some other countries, 2,625 means 2.625 in other countries.

I see that. But how do you do it algebraically? 

1.   10  -80    640    -5120

a_n  = 10 (-8)^n-1

2.  (1/2)(4/3) ^n-1

a₁  = (1/2),  a_n   = (4/3)a_n-1

1.  The first term is 7.....only one answer has a first term  = 7

2.

8, 6, 4 , 2

The difference  in the successive term  to the previous term  is -2

And the first term is 8

So we have

a₁  = 8 , a_n  = a_n-1 - 2     ⇒  first answer

3.  

-3, 1, 5 ,9

a_n   =  -3  + 4(n - 1) ⇒  first answer

Subbing x for t......look at the graph here, Julius

https://www.desmos.com/calculator/6wqntzjcax

The graph has a positive slope  from  [0, 3]....so the max is reached at 3 months  ≈  512.733 (thousands)

Thanks so much Omi67!  Just wanted to check on #2 though, the area of OBC is 2,625?  Or are you using the French (I think it's French) system where , is a decimal point?

Hello quilly!

Yeah, like everyone said, it's a forum where you can answer and ask questions about math.

At times, people post some stuff that are fun, but there's been like a "dead" streak for about 2 months now...

You're not forced to post something that is not related to math. In fact, you'll probably get more views and likes when you post something that is funny...

But yeah, like ElectricPalov said, for private conversations, use messaging.

You know, I've been waiting for something other than math to pop up for a very long time... so this is interesting

Don't worry, it seems like everyone here likes new members.

I'm hoping everyone will liven things up here now. Not everything needs to be math-y...

But...yeah. Don't post random stuff for no reason and continuously posting un-math-y stuff isn't really a good idea. There are people who need help with their math here.

And no, this post is not considered spam. You can post something like this occasinally and everything will be fine.

$f(x)=\frac{x+6}{\sqrt{x^2-3x-4}}$

Note that     x^2 - 3x - 4    must be >  0

Set  this to 0

x^2  -3x - 4  = 0

(x - 4) ( x + 1)  = 0

Setting each factor to  0   and solving for x gives us

x = -1    and x  = 4

We have three  possible intervals

(-inf , -1)  U (-1, 4)   U (4, inf)

Testing x  = 0   in the middle interval makes the polynomial negative....so....this interval does not work

The domain is the other two intervals ⇒    (-inf, -1)  U  ( 4, inf )

Here's a graph  :   https://www.desmos.com/calculator/axfthxpp5t

Great answers, Omi....!!!!

What is the sum of all digits from 1 to 1,000. Just to make it very clear, the question is about the sum of each individual number.

Example: 11 =1 + 1 =2, 12= 1 + 2 =3..........97=9 +7 =16.....991 =9+9+1=19......and so on from 1 to 1,000.

$\text{Let $ b = $ numeral system } \\ \text{Let $ s = $ sum of all digits from $1$ to $b^n$ }$

$Formula:\\ \begin{array}{|rcll|} \hline s &=& 1 + n\cdot b^n \cdot \left( \dfrac{b-1}{2} \right) \\ \hline \end{array}$

$Example:\\ \begin{array}{|rcll|} \hline b &=& 10 \\ n &=& 3 \\ \text{from $1$ to $1000$ } : \\ s &=& 1 + 3\cdot 10^3 \cdot \left( \dfrac{10-1}{2} \right) \\ &=& 1 + 3000 \cdot \left( \dfrac{9}{2} \right) \\ &=& 1 + 13500 \\ &=& 13501 \\ \hline \end{array}$

Welcome, quilly!  

  This site has been around for about 5 years. It is a MATH forum where you can get any MATH questions you may have answered by real people. Anyone who happens to be signed on can answer (or attempt to answer), your Q's.  The answers may have an explanation (usually...but not always).......and there are no guarantees they are correct....but they usually are.

  Please try to keep your posts related to MATH if possible....if you have a follow up question about an answer you have seen posted, please post in to the original thread to avoid confusion and clutter on the forum site.  Please ....DON'T post the same question multiple times.   Sometimes looking at others Q's will find the answer for which you are looking.  We are not here to do all of your homework, but rather here to assist you with understanding your homework so YOU can do it.

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I have never used Yahoo Answers, so I do not know how it compares !

Have fun !