• Want to take part in this year's BoS Trials event for Maths and/or Business Studies?
    Click here for details and register now!
  • YOU can help the next generation of students in the community!
    Share your trial papers and notes on our Notes & Resources page

Polynomial question (1 Viewer)

Joshmosh2

Member
Joined
Mar 30, 2014
Messages
181
Gender
Male
HSC
2015
P(x) is an even function and passes through the point (1,2). What is the remainder when P(x) is divided by (x+1)?

The possible answers were
a) 0
b) -1
c) 1
d) 2

What I thought was that since P(x) is an even function, P(-1) = P(1) so the answer is 1?
Not 100% sure about this one. Any help is greatly appreciated.
 
Last edited:

seventhroot

gg no re
Joined
Aug 3, 2014
Messages
2,803
Gender
Male
HSC
2013
since it is an even function; it must have symmetry about the y axis but is there more to the question? it seems a little incomplete

this looks more MX1 to me
 

Joshmosh2

Member
Joined
Mar 30, 2014
Messages
181
Gender
Male
HSC
2015
since it is an even function; it must have symmetry about the y axis but is there more to the question? it seems a little incomplete

this looks more MX1 to me
Oh I forgot, the polynomial passes through (1,2) .. LOL
 

Joshmosh2

Member
Joined
Mar 30, 2014
Messages
181
Gender
Male
HSC
2015
Not quite. The function has 5 roots (notice the HPOI at the origin) so it will look more like a 'W' shaped quartic. The triple root at the origin becomes a double root when differentiated and the max and mins become roots of f'(x).

I got something that looks like this: http://www.wolframalpha.com/input/?i=y=50x^2(x-1)(x+1)
Mine looked like that too. If the min of the function was placed much lower, for example like this: http://imgur.com/m8fDWP5
Would that correlate to a steeper part for that quartic?
 

emilios

Well-Known Member
Joined
Jan 31, 2013
Messages
667
Gender
Male
HSC
2014
Mine looked like that too. If the min of the function was placed much lower, for example like this: http://imgur.com/m8fDWP5
Would that correlate to a steeper part for that quartic?
Yes. Essentially the 'lower' placement of the min means the gradients of f(x) around the point are much larger i.e. the quartic will be steeper
 

seventhroot

gg no re
Joined
Aug 3, 2014
Messages
2,803
Gender
Male
HSC
2013
Not quite. The function has 5 roots (notice the HPOI at the origin) so it will look more like a 'W' shaped quartic. The triple root at the origin becomes a double root when differentiated and the max and mins become roots of f'(x).

I got something that looks like this: http://www.wolframalpha.com/input/?i=y=50x^2(x-1)(x+1)
oops, I miscalculated 1+3+1 ._.

Essentially the graph "looks like" ax^5 so draw the derivative as bx^4
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top