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#76 Puzzles and Games » Prove that » 2009-03-27 23:14:38

tony123
Replies: 1

Prove that the square of any odd number is always 1 more than a multiple of 8.

#78 Puzzles and Games » How many » 2009-03-18 12:35:31

tony123
Replies: 1

How many even integers between 4000 and 7000 have all digits different?

#79 Re: Puzzles and Games » x » 2009-03-12 19:23:39

nice mathsyperson
but how

#81 Puzzles and Games » m(AED )= 90° » 2009-02-28 20:39:01

tony123
Replies: 1

Let ABC be an isosceles triangle with AB = AC. Let X ad Y be points on sides
BC and CA such that XY // AB. Denote by D the circumcenter of triangle
CXY and by E be the midpoint of BY . Prove that m(AED )= 90°.

#82 Help Me ! » Evaluate the sum » 2009-02-16 09:21:21

tony123
Replies: 5

Suppose that the real numbers

satisfying




Evaluate the sum

#83 Exercises » r is a root » 2009-02-05 04:06:55

tony123
Replies: 3

Suppose r is a root of the polynomial


What is

#84 Exercises » divisible by » 2008-12-07 02:14:03

tony123
Replies: 2

let

integers

and

prove that

divisible by
,

OR
OR
divisible by

#85 Help Me ! » In how many ways » 2008-12-03 08:52:21

tony123
Replies: 1

In how many ways can one distribute 6 apples, 7 bananas, and
8 cantaloupes between 10 people? All fruit of the same type are identical.
Fruit must remain whole, must all be given out, and possibly Alphonse gets
everything.

#86 Puzzles and Games » how old is jane now? » 2008-12-02 07:19:37

tony123
Replies: 3

jane and olivia both celebrate their birthday today. In three years, jane
will be four times as old as olivia  was when jane was two years older than
olivia  is today. If olivia  is a teenager, how old is jane now?

#87 Help Me ! » Solve the equation » 2008-11-30 22:23:55

tony123
Replies: 1

Solve the equation


on the set of real numbers.

#89 Exercises » Find the minimum » 2008-11-30 08:32:57

tony123
Replies: 1

Find the minimum value of

.

#90 Exercises » the remainder » 2008-11-29 06:27:21

tony123
Replies: 6

What is the remainder when 

6^83 + 8^83 is divided by 49?

#92 Exercises » cos(x - y) » 2008-11-22 22:23:49

tony123
Replies: 8

Prove that if


and
,
then

#94 Puzzles and Games » Magic square » 2008-11-10 10:21:54

tony123
Replies: 4

Fill in the Magic square 5×5 with numbers from 1 to 25 such that the side totals and diagonal totals equal 65.


#95 Exercises » Let integer p and q » 2008-11-09 08:15:48

tony123
Replies: 2

Let integer p and q

Prove that     

#97 Exercises » how many positive integers » 2008-11-08 23:01:05

tony123
Replies: 2

For how many positive integers n is

an integer ?

#98 Help Me ! » matrices » 2008-11-07 07:32:22

tony123
Replies: 2

Suppose

are n × n matrices with entries in a feld F,

satisfying the conditions that

and


are symmetric and

Here I is the n × n
identity matrix, and if M is an n × n matrix,

is its transpose.

Prove that

#100 Exercises » how many » 2008-11-01 07:46:30

tony123
Replies: 1

It is possible to replace each of the ± signs below by either – or + so that

± 1 ± 2 ± 3 ± 4 ± ... ± 96 = 1996.

At most how many of the ± signs can be replaced by a + sign?

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