Wednesday

April 16, 2014

April 16, 2014

Posted by **ianian** on Monday, April 29, 2013 at 4:13am.

- Maths -
**Reiny**, Monday, April 29, 2013 at 8:26amso we are looking for

1 + x^2 + x^4 being a prime

x^4 + x^2 + 1

= x^4 + 2x^2 + 1 - x^2

= (x^2 + 1)^ - x^2 ---- a difference of squares

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

if x = 1 , we get

(1+1+1)(1) = 3 --- a prime number

for any other value of x, the value of each bracket > 1

and 1+x^2 + x^4 is the product of at least two factors

thus : 1 + 1^2 + 1^4 is the only such case

1 1 1 is the only case

- Maths -
**tsong**, Monday, April 29, 2013 at 11:13am111 is incorrect

- Maths -
**PD**, Tuesday, April 30, 2013 at 2:57pm@Tsong, the answer is not 111, the answer is 3 :P

- Maths -
**PD**, Tuesday, April 30, 2013 at 2:58pmsorry, the answer is 1 :P

- Maths -
**abc**, Saturday, May 4, 2013 at 2:57amthanxxxx

**Related Questions**

Math - Consider all 3-term geometric sequences with first term 1 and with common...

algebra - Consider all 3-term geometric sequences with first term 1 and with ...

arithmetic - An arithmetic n geometric sequence have the same first term 2.with ...

Maths - Eric thinks of 2 sequences.One is geometric and the other arithmetic....

Maths - An arithmetic and a geometric sequence have the same first terms.(2).......

Maths - A geometric progression has a third term of 20 band sum to infinity ...

Geometric progression - The second term of a geometric progression is 12 more ...

Maths - 1..The first 2 terms of a geometric progression are the same as the ...

arithmetic - first term and larst term of a geometric progression is 42.if the ...

Mathematics. Geometric sequences. - 2+4+8+...is a geometric sequence. Prove the ...