How do you use the Binomial theorem to expand (5+2i)^4(5+2i)4?

1 Answer
Mar 27, 2018

(5+2i)^4=41+840i(5+2i)4=41+840i

Explanation:

According to Binomial Theorem

(a+b)^4=C_0^4a^4+C_1^4a^3b+C_2^4a^2b^2+C_3^4ab^3+C_4^4b^4(a+b)4=C40a4+C41a3b+C42a2b2+C43ab3+C44b4

= a^4+4a^3b+6a^2b^2+4ab^3+b^4a4+4a3b+6a2b2+4ab3+b4

Hence (5+2i)^4(5+2i)4

= 5^4+4*5^3*2i+6*5^2*(2i)^2+4*5*(2i)^3+(2i)^454+4532i+652(2i)2+45(2i)3+(2i)4

= 625+1000i+600i^2+160i^3+16i^4625+1000i+600i2+160i3+16i4

= 625+1000i-600-160i+16625+1000i600160i+16

= 41+840i41+840i