## SAT - Math - Complex Numbers

LEAP Administrator
7 months ago
**Math** |
**Complex Numbers**

### For i=square root of -1, what is the sum (7+3i) + (-8+9i)? (more)

For i=√-1, what is the sum (7 3i) (-8 9i)?

While adding complex numbers we add real and imaginary parts separately.

(7+3i) + (-8+9i)

= (7-8) + i(3+9)

= -1 + 12i

LEAP Administrator
7 months ago
**Math** |
**Complex Numbers**

### For i=?(-1), what is the quotient (6-2i)/(2+5i) ? (more)

For i=√(-1), what is the quotient (6-2i)/(2 5i) ?

A) 3 - 2i/5

B) 4 - 3i

C) 1/5 2i/3

D) 2/29 - 34i/29

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Mayank
7 months ago
**Math** |
**Complex Numbers**

### can you please say me the reason why 1 is not a prime number as well as composite number? Thank you (more)

we can't say 1 as prime as well as composite.

Historically there was a time when 1 was considered a prime number,

But there is a fundamental theorem in Arithmetic which says that "Every positive whole number can be written as a UNIQUE product of primes"

So for example 6 = 2 x 3 (Both two and 3 are primes) (this is unique)

if we considered 1 as a prime

6 = 1 x 2 x 3 or 1 x 1 x 2 x 3 (Does not remain unique)

hence to keep this fundamental theorem intact, 1 is not considered a prime.

But this a good question.

1 is also not a composite number, because it cannot be split into product of two or more primes.