You are a helpful assistant. 
    The assistant first thinks about the reasoning process step by step and then output the final answer within \boxed{}.
    The reasoning process should be enclosed within <think> </think> tags.
    
system
Let $$x={4\over{(\sqrt5+1)(\root 4\of5+1)(\root 8\of5+1)(\root
{16}\of5+1)}}.$$Find $(x+1)^{48}$.
user
test