Publisher Summary This chapter discusses complex numbers. In rectangular form of complex number, every number expressible in the form x + yi, where x and y are real numbers and i =, is called a complex number. The complex number x - yi is called the conjugate of x + yi. In polar form, with each complex number is associated a magnitude and a direction. The product of two complex numbers in polar form is, in general, a complex number whose absolute value is the product of the absolute values and whose amplitude is the sum of the amplitudes. This chapter also discusses series representation. Series in which the number of terms is unlimited is called an infinite series. An infinite series is said to converge or be convergent if the partial sums Sn tend to some finite value S as n becomes arbitrarily large.