Register
Login
Username
Password
Login
forgot your password?
Home
Forum
+0
Formulary
Maths
Help
Complex Numbers
Integral Calculus
Differential Calculus
Equations
Graphs
Linear Algebra
Number theory
Percent
Standard Functions
Statistics
Trigonometry
Unit Conversion
Units
About
Imprint
Privacy Policy
Terms of Service
Credits
Google+
Facebook
Contact Email
Post New Question
All Questions
+0
230619 Questions
0
383
1
help
A magical prime is a number that is prime, and all its digits add up to a prime number. How many magical primes are there between 100 and 160?
●
Guest
Dec 3, 2019
0
438
2
help
How many numbers between 10^6 and 10^7 have a digit sum of 2?
●
●
Guest
Dec 3, 2019
0
411
0
Matrix Proofs
Show that is also symmetric if a matrix is symmetric when .
If A is an idempotent matrix, show that (A+B)(A+I) = 2A + BA + B, where I is the identity matrix.
Guest
Dec 3, 2019
0
845
0
+700
How does adding high or low values affect your mean and standard deviation?
this is a question that is really making me struggle and i dont understand the point of it and how it works..... lets say
i had some random data:
the mean is 88
and the standard dev = 5
what if i added another number such as 88 lets
read more ..
Nirvana
Dec 3, 2019
0
444
1
help
It is 2 AM now. What time is it 3736 hours from now?
●
Guest
Dec 3, 2019
0
513
1
help
If x^2 + 1/x^2 = 171, then what are the possible values of x - 1/x?
●
Guest
Dec 3, 2019
0
639
1
help
There are 32 socks in a bag consisting of 16 black socks and 16 white socks. What is the minimum number of socks you must take to make sure that you have three pairs of socks, where each pair has the same color?
●
Guest
Dec 3, 2019
0
494
1
help
Compute 2*arctan(1/3) + arctan(1/7).
●
Guest
Dec 3, 2019
0
753
4
help
Find the number of 3-digit numbers, where any two adjacent digits differ by 1.
●
●
●
●
Guest
Dec 3, 2019
0
951
1
help
Solve the puzzle PQR * 3 = QQQ, where each letter stands for a different digit.
●
Guest
Dec 3, 2019
0
594
1
help
There are 5 boys and 6 girls in a class. A committee of three students is to be made such that there is a boy and a girl on the comittee. In ho w many ways can the committe be selected?
●
Guest
Dec 3, 2019
0
681
3
help
How many 4 -digit positive integers have 2 or more zeroes?
●
●
●
Guest
Dec 3, 2019
0
365
0
help
In the single-elimination NCAA Tournament, 64 teams compete in 6 bracketed rounds. How many games are there in total?
read more ..
Guest
Dec 3, 2019
0
696
2
help
How many triangles are there in the diagram above?
●
●
Guest
Dec 3, 2019
0
389
1
help!! exponential functions
Just this question:
●
Guest
Dec 3, 2019
0
465
1
help
If a + b + c = 8 and ab + ac + bc = -2, what is a^2 + b^2 + c^2?
●
Guest
Dec 3, 2019
0
886
1
Please help, ASAP. I'm building on these concepts soon!
1) In triangle $XYZ,$ $M$ is the midpoint of $\overline{XY}.$ Let $D$ be the point on $\overline{YZ}$ such that $\overline{XD}$ bisects $\angle YXZ,$ and let the perpendicular bisector of $\overline{XY}$ intersect $\overline{XD}$ at $P.$ If $XY = 36$ and
read more ..
●
Guest
Dec 3, 2019
0
501
2
help
The length of a certain rectangle is increased by 20% and its width is increased by 30%. Then its area is increased
by how much?
●
●
Guest
Dec 3, 2019
0
592
1
help pleez
Two squares with side 8 and 4 are drawn side by side,Find the area of shaded region.
●
Guest
Dec 3, 2019
0
697
2
help please
Completely factor x^8 - y^8.
●
●
Guest
Dec 3, 2019
0
628
1
9 5-x = 1/(sqrt(15 4x ))
95-x = 1/(sqrt(154x))
●
Guest
Dec 3, 2019
0
506
1
please help
a_1, a_2, a_3, ..., a_{99} is an arithmetic progeression. If a_2 + a_5 + a_8 + ... + a_{98} = 205, then find a_1 + a_2 + a_3 + ... + a_{99}. Be sure to show all your work.
●
Guest
Dec 3, 2019
0
592
1
please help
For a certain arithmetic progression, the sum of the first 1729 terms is equal to the sum of the first 29 terms. Find, with proof, the sum of the first 1758 terms. Show all your steps!
●
Guest
Dec 3, 2019
0
500
1
help
An arithmetic progression has 10 terms. The sum of the last five terms is 85. If the fourth term is 9, then find the sum of all 10 terms.
●
Guest
Dec 3, 2019
0
991
4
please help ASAP thank you so much in advance
(a) Compute the sum \[ 101^2 - 97^2 + 93^2 - 89^2 + \cdots + 5^2 - 1^2.\]
(b) Compute the sum \[ (a +(2n+1)d)^2- (a + (2n)d)^2 +(a + (2n-1)d)^2 - (a+(2n-2)d)^2 + \cdots + (a+d)^2 - a^2.\]
I would prefer it if the answers
read more ..
●
●
●
●
Guest
Dec 3, 2019
«
latest
9223
9222
..
6148
6147
6146
6145
6144
..
2
1
»
Post New Question
1 Online Users
Top Users
+128475
CPhill
moderator
+118609
Melody
moderator
+33616
Alan
moderator
+14915
asinus
moderator
+9519
MaxWong
+3144
admin
administrator
+2440
GingerAle
+1791
tomtom
+1484
bader
+1101
parmen
+1032
kittykat
Sticky Topics
Some guidelines for question askers.
What is Happening 5
Again a number puzzle. Multiply in writing.
Loads of fun printable number and logic puzzles
¤¤¤¤Welcome To Web2.0calc¤¤¤¤
How to display latex properly
Feature Questions 1 - Started 8th May 19
How to upload a picture.
If a question is ticked that does not mean you cannot continue it.
Should you consider anything before you answer a question?
Geometry Thread
PUZZLES
LaTex Coding
/calculator/bsh9ex1zxj
Historical post!
What is happening? Wrap #4
Great Questions to Learn From 2
Great Answers to Learn From
Reference Material
Information for new people.