New Year Function

Algebra Level 4

A d e g r e e 5 p o l y n o m i a l g i v e s t h e f o l l o w i n g v a l u e s : P ( 1 ) = P ( 2 ) = P ( 3 ) = P ( 4 ) = P ( 5 ) = 1 F i n d P ( 2015 ) 1 P ( 2014 ) 1 = a b i n l o w e s t f o r m . F i n d a + b . A\quad degree\quad 5\quad polynomial\quad gives\quad the\quad following\quad values:-\\ P(1)=P(2)=P(3)=P(4)=P(5)=1\\ \\ Find\quad \frac { P(2015)-1 }{ P(2014)-1 } =\frac { a }{ b } \quad in\quad lowest\quad form.\quad Find\quad a+b.


The answer is 4023.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

From the given fact that:

P ( 1 ) = P ( 2 ) = P ( 3 ) = P ( 4 ) = P ( 5 ) = 1 P(1)=P(2)=P(3)=P(4)=P(5)=1

P ( x ) = A ( x 1 ) ( x 2 ) ( x 3 ) ( x 4 ) ( x 5 ) + 1 \Rightarrow P(x) = A(x-1) (x-2) (x-3) (x-4) (x-5)+1

Therefore,

P ( 2015 ) 1 P ( 2014 ) 1 \dfrac {P(2015)-1}{P(2014)-1}

= A ( 2015 1 ) ( 2015 2 ) ( 2015 3 ) ( 2015 4 ) ( 2015 5 ) + 1 1 A ( 2014 1 ) ( 2014 2 ) ( 2014 3 ) ( 2014 4 ) ( 2014 5 ) + 1 1 = \dfrac {A(2015-1) (2015-2) (2015-3) (2015-4) (2015-5)+1-1}{A(2014-1) (2014-2) (2014-3) (2014-4) (2014-5)+1-1}

= A ( 2014 ) ( 2013 ) ( 2012 ) ( 2011 ) ( 2010 ) A ( 2013 ) ( 2012 ) ( 2011 ) ( 2010 ) ( 2009 ) = 2014 2009 = \dfrac {A(2014) (2013) (2012) (2011) (2010)}{A(2013) (2012) (2011) (2010) (2009)} = \dfrac {2014}{2009}

a = 2014 \Rightarrow a = 2014 , b = 2009 b = 2009 and a + b = 2014 + 2009 = 4023 a+b = 2014+2009 = \boxed{4023}

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...