Hi
Got problem with these questions any suggestions?
Show that 2-i is a root of z^4 - 8z^3+28z^2-48z+35. Hence find all roots
and
Find all 5th roots of -32 and all 4th rots of 81i
In form x+iy where x and y in 4 DP
Thx
all the coefficients of the quartic are real so the complex conjugate is a root.
so we have two factors and .
so is a factor of your quartic, divide your quartic by this factor and then solve the quadratic to get the two remaining roots.
you want the solve the equation . first rewrite -32 in the form ofFind all 5th roots of -32 and all 4th rots of 81i
tell me how it goes
Bobak
Two things you should know:
1. If is a root then is a linear factor.
2. If a polynomial has real coefficients and is a root, then , the conjugate of , is also a root.
Some of the questions you're asking suggest it would be a good thing for you to go back and thouroughly review this whole topic.