Write [2(cos15*+isin15*)]^3 in standard form a+bi

Hello : 
by moivre theorem : 
[2(cos15*+isin15*)]^3 = 2^3(cos(3×45*)+isin(3×45*))
                                   =8 (cos45*+isin45*)
                                   = 8 ( √2/2 +i √2/2)
                                   = 4√2 + 4√2 i ( in standard form a+bi)
a = b = 4√2 

The answer would be the second choice : )