MHB Why x2 +1 and x2 -1 are Not/Are Difference of Squares

  • Thread starter Thread starter Abdullah Qureshi
  • Start date Start date
  • Tags Tags
    Difference Squares
Abdullah Qureshi
Messages
16
Reaction score
0
Explain why x2 +1 is not a difference of squares and x2 -1 is
 
Mathematics news on Phys.org
Oh, but it is ...

$x^2+1 = x^2 - (-1) = (x - i)(x + i)$
 

Thread 'Trigonometry problem of interest'

Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...
View full post »

Thread 'Six Pencil Puzzle'

Is it possible to arrange six pencils such that each one touches the other five? If so, how? This is an adaption of a Martin Gardner puzzle only I changed it from cigarettes to pencils and left out the clues because PF folks don’t need clues. From the book “My Best Mathematical and Logic Puzzles”. Dover, 1994.
View full post »

Similar threads

MHB Square metric not satisfying the SAS postulate
Replies
3
Views
4K
B Why is x2 . y2 not equal to (x-y) (x+y)?
Replies
1
Views
1K
I Understanding a quote about implicit differentiation
Replies
4
Views
1K
MHB Tell me, must I use m = (y2 - y1)/(x2 - x1), where m is 1/4?
Replies
12
Views
2K
MHB Intersection points of two quadratic functions
Replies
1
Views
2K
B Combinatorics and Magic squares
Replies
2
Views
2K
MHB Finding Squares in a Square Box: n > 1
Replies
1
Views
1K
I What does negative ratio mean in mathematics?
Replies
18
Views
19K
MHB Average rate of change in the function from x1 to x2
Replies
5
Views
3K
B Understanding why πr^2 works for different area calculations
Replies
7
Views
2K

Hot Threads

Recent Insights

Back
Top