 Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫  π  -¹ ² ³ °

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## #1 Re: Formulas » Set Theory » 2014-12-29 23:08:58

Set theory is a mathematical theory of well determined collections, sets of objects that are called members or elements. Set theory is very simple theory but the concept of it is little bit difficult.

## #2 Re: Formulas » Symbols » 2014-12-29 22:43:16

I noted down all the symbols that was given here and also other symbols which was important for me and posted in others. All the symbols are really important for me.

## #3 Re: Formulas » Vedic Math - Trick 1 » 2014-12-29 22:36:28

I was not getting the concept of this trick clearly I was confuse from the second line.

For example 1000 - 357 = 643
We simply take each figure in 357 from 9 and the last figure from 10.

If you can clarify then please clear this line so that I can understand this trick.

## #4 Re: Formulas » Tests For Divisibility » 2014-12-29 22:32:21

Thanks for posting this formulas here, I really like doing the divisibility test in maths. I learn this formulas when I was in middle school. But I learn it till the the divisibility test by eight only, I didn't know the further more divisibility test given here.

## #5 Re: Formulas » Rational Numbers » 2014-12-29 22:17:16

ShivamS wrote:

Yes, I should have clarified. After you use the specified formula, you get the Rational # in between by: x+d, x+2d, x+3d...x+nd. To give an example, lets say we have to find 3 rational numbers between 2 and 3. Therefore: x=2 y=3 n=3. Thus, d= (3-2)/(3+1)=1/4. So the n numbers are: 2 1/4, 2  2/4 and 2 3/4. This is fairly obvious, I just wanted to give the generalized formula.

Yes I agree with you I also use this formula of rational number and I got the actual answer.

## #6 Re: Formulas » Standard Deviation » 2014-12-29 22:05:16

Standard deviation is a quantity calculated to indicate the extent of deviation for a group. I don't think it will work for points distributed in 3-axis.

## #7 Re: Maths Teaching Resources » Learning Graph Theory » 2014-12-14 23:21:15

There are lots of sites which can provide you pdf notes of graph theory and you can download some Ebooks also to get deep knowledge in graph theory.

## #8 Re: Maths Teaching Resources » Graphing Calculator » 2014-12-14 23:16:25

There is lots of sites but they only have some limited fetures, if you want to all type of graphs then you should purchase a graphic calculator.

## #9 Re: Maths Teaching Resources » Great Math apps. » 2014-12-14 23:13:38

Math is a subject that is totally based on formulas there are thousands of formulas used in maths, it is not possible to remember all of those formulas you can take help from some apps like Math formulas and Physics formulas.

## #10 Re: Formulas » Supplement Multiplication » 2014-12-12 00:20:57

Wow, it is a great formula, maths always rocks. You don't need any calculator or long calculation for multiplying two numbers which is more than 100.

## #11 Re: Formulas » Calculating day of the week » 2014-12-12 00:10:58

Excellent. The formula in the site you have suggested is excellent, i have also tied to calculate some days of the weak and got succeed by the formula.
Thank for sharing. Now i can also calculate only in 3 minutes.

## #12 Re: Formulas » same x and y coordinates » 2014-10-30 23:38:06

Not getting the question, geometrical question is not getting me properly.

## #13 Re: Formulas » fixed cost » 2014-10-30 23:29:43

bobbym wrote:

If I am remembering it right, the y intercept is the fixed cost. You are correct that is b.

Yes agree, you are exactly correct. Y intercept is the fixed cost.

## #14 Re: Formulas » Quartic formula » 2014-10-30 23:23:02

The formula is very nice, once we start solving the question by using the above formula, then we can easily remember the above formula. Not too difficult to remember the above formula.

It is not easy to remember all this formula, few formula we can remember because there are some formulas which are like some basic formulas which we can use sometimes.

## #15 Re: Formulas » value » 2014-10-30 23:11:59

You use the formula of three points lying in the same line and find all the points of the line.  First you have to find the slope of the line then find by equation of line "y-y1=m(x-x1). Then definitely you will get its answer.

## #16 Re: Formulas » line intersections » 2014-10-30 23:02:02

Answer is "the same" if two lines intersect on more then one point then they are in the same.

## #17 Re: Formulas » common mistake » 2014-10-30 22:49:24

Thank for explaining this exponential function here, I completely understand the equation. Here coefficient is different thing and variable is different.

## #18 Re: Formulas » Easy Multiplication » 2014-10-30 22:43:10

Hostible wrote:

MULTIPLES OF 3

3 times even number

Rule
a. Write half of the multiplier and put 0 at the end.
b. Double the multiplier and subtract it from Rule (a).

Examples:

3 x 4; Half of 4 is 2. Put 0 at the end to form 20.
Take away twice the multiplier. Twice of 4 is 8. 20-8 = 12.
Therefore 3 x 4 = 20.

All the rules are excellent and correctly giving the answer. But the above rule is not getting me properly I think it is wrong please give the correct rule for above.

## #19 Re: Formulas » Complement Multiplication » 2014-10-30 22:32:03

The trick you have given to solve the multiplication problem of such a big number is really excellent. I like this trick very much, I have one question that can it will also work in multiplication of three digit number.

## #20 Re: Formulas » Temperature » 2014-10-30 22:22:42

byronjordan wrote:

Celsius to Fahrenheit is not 9/5 of (C+32)  Nor (C+32)x9/5.

It is (9/5 of C)+32.

For example 0C is 32F, as the most obvious example. 9/5 of (0C+32) is not equal to 32F, but (9/5 of 0C)+32 is equal to 32F. The formual (9/5 of C)+32 also works on other perhaps obvious examples, like 100C is 212F and -40C is -40F.

Yes you are right, the formula posted in thread was wrong, only right hand side is correct left hand side is not correct. The correct formula is that which is posted by you.