Complex Q (1 Viewer)

[krypticlemonjuice]

How is the answer to this q A?

 

[gazzaboy]

One way to quickly see this to to substitute a point into the equation. The easiest would be the one on the left with argument pi. In other words, this is just some negative number. If you take some negative number to the power of 5, you get a negative number. This means that a must be a positive number.

 

[krypticlemonjuice]

One way to quickly see this to to substitute a point into the equation. The easiest would be the one on the left with argument pi. In other words, this is just some negative number. If you take some negative number to the power of 5, you get a negative number. This means that a must be a positive number.

What do you mean there must be a positive number ?

 

[Drongoski]

is a polynomial equation (of degree 5) whose roots are the points on the circle. Since these points are symmetric about the x-axis, it means every (of the 4) complex roots appear in complex-conjugate pairs. Therefore the coeffs of this polynomial eqn must be all reals; therefore 'a' must be real. So answer cannot be C) or D). Cannot be B) or else one of the roots would be a positive real number.