Write the complex number on the form , and then compute
There is no simple exact answer to the question you have posted. This has been said several times now.
So either the question has a mistake in it or an approximate answer is required. If the former, then the likely question and its answer has been given in this thread. If the latter, the answer has also been given.
I don't see how any further progress can be made here unless the OP is prepared to acknowledge and address the above issues.
As you can see your exact solution is a bit off.
Go to Wolfram|Alpha. Type “((sqrt[3]+1)/2)^69” exactly then click the “=” at the right-hand side of the input box.