# Putnam inspired problem

The following is a beautiful problem from Putnam 2003

minimize $|\sin x + \cos x + \tan x + \csc x + \sec x + \cot x|$

I was thinking about a small variation of the above problem

minimize $|\sin x + \cos x + \tan x - \csc x - \sec x - \cot x|$

Thanks.

• Both these values blow up certain trigonometric functions. So incorrect – user136833 Mar 20 '14 at 17:51
• Is there a certain limit for $x$? $[0,\frac{\pi}{2}]$, for example? – 2012ssohn Mar 20 '14 at 17:52
• @2012ssohn the original Putnam problem had no such limits. But then you naturally expect it to lie in $(-\pi, \pi)$ since the functions are periodic – user136833 Mar 20 '14 at 17:54
• Can you represent each as complex exponentials then simplify? – Erik M Mar 20 '14 at 17:55
• Ok. I was wondering about the original Putnam problem, and it seems to blow up at $x = 0$, and was wondering whether there are any limitations. – 2012ssohn Mar 20 '14 at 17:56

Let $x=-\dfrac{\pi}{4}$. Then $\cos x = -\sin x, \sec x = -\csc x, \tan x = \cot x$ and the expression inside the absolute values is $0$.
• Adding integer multiples of $\pi$ gives you more zeros – David H Mar 20 '14 at 18:00