Express the following complex numbers in the standard form a + i b :
(1 + i) (1 + 2i)
Given:
⇒ a+ib = (1+i)(1+2i)
⇒ a+ib = 1(1+2i)+i(1+2i)
⇒ a+ib = 1+2i+i+2i2
We know that i2=-1
⇒ a+ib = 1+3i+2(-1)
⇒ a+ib = 1+3i-2
⇒ a+ib=-1+3i
∴ The values of a, b are -1, 3.