Answer:
There are seven seventh roots of unity, e2πki7 , all on the unit circle, r=1 above.
The first one is at θ=2π7=360∘7=5137 ∘ , and there are others at 4π7,6π7,8π7,10π7,12π7 and of course at 0 radians, i.e. unity itself.
How to find?
There are 4 fourth roots of unity and they are 1, i,−1 and−i
Each of the roots of unity can be found by changing the value of k k k in the expression e 2 k π i / n e^{2k\pi i/n} e2kπi/n. By Euler's formula, e 2 π i = cos ( 2 π ) + i sin ( 2 π ) = 1.
My answer: $2000 were invested at 5%
Let x amount of money was invested at 5% and (6000-x) amount was invested as 3%
We have a fraction with the unknown in the denominator, review how to treat unknowns in the denominator as a refresher for this exercise:
<span>(2/3) - (1/x + 6) = 2
</span>(2/3) - (1 + 6x)/x = <span>2
</span>(2/3) - 2 = (1 + 6x)/x
2/3 - 6/3 = (1 + <span>6x)/x
-4/3 = </span>(1 + <span>6x)/x
-4x = 3</span>(1 + <span>6x)
</span><span>-4x = 3 + 18x
</span>22x = -3
x = -3/22
The correct answers are
1. 2c+b-c
2. 31