Is this quadratic in $n$ ?

Algebra Level 1

If $f(x) = n ( x - n )$ for a constant $n$ , what is the value of

$f( 2015) - f ( 2013)?$

n^2

2014 n

2n

n

1 solution

L S
Jan 30, 2015

$f(2015)-f(2013)$

$=n(2015-n)-n(2013-n)$

$=2015n-n^2-2013n+n^2$

$=2n$

An easy 100 pointer . no ?

A Former Brilliant Member - 6 years, 4 months ago

Another way of thinking of this question, is that $f(x)$ is actually a linear equation (in $x$ ), and hence we know that $f(x+2) - f(x)$ is a constant, equal to twice the slope, i.e. $2n$ .

I added in the fact that it was quadratic in $n$ to add some confusion.

Chung Kevin - 6 years, 4 months ago

Is this quadratic in n n n ?

1 solution

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Is this quadratic in $n$ ?