Difference between revisions of "1969 IMO Problems/Problem 2"

m
m
Line 8: Line 8:
  
 
{{IMO box|year=1969|num-b=1|num-a=3}}
 
{{IMO box|year=1969|num-b=1|num-a=3}}
[[Category:Olympiad Geometry Problems]]
 

Revision as of 14:01, 17 February 2018

Problem

Let $a_1, a_2,\cdots, a_n$ be real constants, $x$ a real variable, and \[f(x)=\cos(a_1+x)+\frac{1}{2}\cos(a_2+x)+\frac{1}{4}\cos(a_3+x)+\cdots+\frac{1}{2^{n-1}}\cos(a_n+x).\] Given that $f(x_1)=f(x_2)=0,$ prove that $x_2-x_1=m\pi$ for some integer $m.$

Solution

This problem needs a solution. If you have a solution for it, please help us out by adding it.

See Also

1969 IMO (Problems) • Resources
Preceded by
Problem 1
1 2 3 4 5 6 Followed by
Problem 3
All IMO Problems and Solutions