Find the square root of 2+5i so that the real part of your answer is positive.

The square root is ?

If I square it i get 4+25i^2
4-25
-21
Which would be -21+0i Right? But how do i make the real part positive and what is the square root?

Question

Find the square root of 2+5i so that the real part of your answer is positive.

The square root is ?

If I square it i get 4+25i^2 
                             4-25
                             -21
Which would be -21+0i  Right? But how do i make the real part positive and what is the square root?

anonymous · Answer

I guess u assume a root of a+ib, square it, then compare real and imaginary parts.

anonymous · Answer

i dont understand

anonymous · Answer

If i do that, I get

2 = a^2-b^2 and

5 = 2ab  to solve.

anonymous · Answer

I guess u could also use DeMoivre, if u know that way...

anonymous · Answer

um... not to make myself look ignorant but I dont know what you mean where did (2 = a^2-b^2 and 5 = 2ab) come from and what is and a and b?

anonymous · Answer

I am assuming there is a square root of the form a + ib so if u square that u get

a^2 + 2abi -b^2 which put equal to 2 + 5i so

a^2-b^2 = 2 and 2ab = 5  equating real and imaginary parts.