This question is not well defined. By 'expi' do you mean exp(i)? In other words, is the expression [exp(i)]^i ? If so, then the answer is undoubtedly exp(-1). You can use Euler's equation to show this, but it is much easier to use this fact about exponents:

Question

This question is not well defined. By 'expi' do you mean exp(i)? In other words, is the expression [exp(i)]^i ? If so, then the answer is undoubtedly exp(-1). You can use Euler's equation to show this, but it is much easier to use this fact about exponents: 
(a^b)^c=a^(bc).

On the other hand, if the function is expi, then I don't know what that function is.

It is important to use parentheses for clarity if you are writing mathematical expressions in ASCII.

sorry, the exact question was exp(i^i) and i found it! it is exp(-Ï€/2)=1.23 
thanks anyway