let $X_1 , ....,X_n$ be iid. $Uniform[-\theta,\theta]$. I need to find the complete sufficient statistic.
I know that $T=(X_{(1)}, X_{(n)} )$ is a sufficient statistic for $\theta$.Also i know T is not a complete sufficient statistic.
I want to prove it. So first I tried to use the Basu's theorem . But in this case $R = X_{(n)} -X_{(1)}, $ is not a ancillary statistic.
So i tried prove using the definition of the complete sufficient statistic.
Here i have attached my work so far.

But by doing like this , seems like that i am going to prove that T is a complete sufficient statistic.
So can someone help to figure it out what i did incorrectly ?
Thank you