- Home
- Standard 11
- Mathematics
4-1.Complex numbers
easy
${(1 + i)^8} + {(1 - i)^8}$ = . . .
A
$16$
B
$-16$
C
$32$
D
$-32$
Solution
(c) $\,{(1 + i)^2} = \,1 + {i^2} + 2i = 2i$and ${(1 – i)^2} = 1 + {i^2} – 2i = – 2i$
$ \Rightarrow {(1 + i)^8} + {(1 – i)^8} = {(2i)^4} + {( – 2i)^4}$$ = {2^4}({i^4} + {i^4})$
$ = {2^5} = 32.$
Standard 11
Mathematics