If ω 0 = 2 0 1 5 and let 1 − ω n 1 + ω n = ω n + 1 , then value if ω 2 0 1 6 is
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.
Just observe a simple recurrence
w(0) = 2015
w(1)= -1008/1007
w(2) = -1/2015
w(3)= 1007/1008
w(4)=2015
Thus for every w(n) where n=4k
we have w(n) = 2015
Thus w(2016)=w(2012)
Let w n = tan ( x n ) for some x n ∈ R and n ∈ N .
This is because the range of tan x is R so any term of sequence(which consists of real terms) is equal to tan x for some x ∈ R
Then 1 − w n 1 + w n = 1 − tan ( x n ) 1 + tan ( x n ) = tan ( 4 π + x n ) = tan ( x n + 1 ) = w n + 1
So we get
w n + 2 = tan ( x n + 2 ) = tan ( 2 π + x n )
w n + 3 = tan ( x n + 3 ) = tan ( 4 3 π + x n )
w n + 4 = tan ( x n + 4 ) = tan ( π + x n ) = tan ( x n ) = w n
We conclude that the sequence is periodic with period n = 4 and hence answer is w 2 0 1 6 = w 2 0 1 2
Since tan ( 2 π + θ ) = tan θ , it follows from the recurrence has a period of 4. How else can we know this?
Not 2 π but π
Problem Loading...
Note Loading...
Set Loading...
w n + 1 w 2 0 1 6 = 1 − w n 1 + w n = 1 − 1 − w n − 1 1 + w n − 1 1 + 1 − w n − 1 1 + w n − 1 = − w n − 1 1 = − w 2 0 1 4 1 = − − w 2 0 1 2 1 1 = w 2 0 1 2