the square root of a negative value is called an imaginary or number
Imaginary number An imaginary number[note 1] is a complex number that can be written as a real number multiplied by the imaginary unit i,[note 2] which is defined by its property i2 = −1.[1] The square of an imaginary number bi is −b2. For example, 5i is an imaginary number, and its square is −25. Zero is considered to be both real and imaginary.[2]
Signed number representations This representation is also called "sign–magnitude" or "sign and magnitude" representation. In this approach, the problem of representing a number's sign can be to allocate one sign bit to represent the sign: setting that bit (often the most significant bit) to 0 is for a positive number or positive zero, and setting it to 1 is for a negative number or negative zero. The remaining bits in the number indicate the magnitude (or absolute value). Hence, in a byte with only seven bits (apart from the sign bit), the magnitude can range from 0000000 (0) to 1111111 (127). Thus numbers ranging from −12710 to +12710 can be represented once the sign bit (the eighth bit) is added. For example, −4310 encoded in an eight-bit byte is 10101011 while 4310 is 00101011. A consequence of using signed magnitude representation is that there are two ways to represent zero, 00000000 (0) and 10000000 (−0).