Answer:
The other pairs are:
[tex](a)\ (2, \frac{5\pi}{6}) \to[/tex] [tex](2, \frac{17\pi}{6})[/tex] and [tex](-2, \frac{23\pi}{6})[/tex]
[tex](b)\ (1, -\frac{2\pi}{3}) \to[/tex] [tex](1, \frac{4\pi}{3})[/tex] and [tex](-1, \frac{7\pi}{3})[/tex]
[tex](c)\ (-1, \frac{5\pi}{4}) \to[/tex] [tex](-1, \frac{3\pi}{4} )[/tex] and [tex](1, \frac{7\pi}{4})[/tex]
See attachment for plots
Step-by-step explanation:
Given
[tex](a)\ (2, \frac{5\pi}{6})[/tex]
[tex](b)\ (1, -\frac{2\pi}{3})[/tex]
[tex](c)\ (-1, \frac{5\pi}{4})[/tex]
Solving (a): Plot a, b and c
See attachment for plots
Solving (b): Find other pairs for [tex]r > 0[/tex] and [tex]r < 0[/tex]
The general rule is that:
The other points can be derived using
[tex](r, \theta) = (r, \theta + 2n\pi)[/tex]
and
[tex](r, \theta) = (-r, \theta + (2n + 1)\pi)[/tex]
Let [tex]n =1[/tex] ---- You can assume any value of n
So, we have:
[tex](r, \theta) = (r, \theta + 2n\pi)[/tex]
[tex](r, \theta) = (r, \theta + 2*1*\pi)[/tex]
[tex](r, \theta) = (r, \theta + 2\pi)[/tex]
[tex](r, \theta) = (-r, \theta + (2n + 1)\pi)[/tex]
[tex](r, \theta) = (-r, \theta + (2*1 + 1)\pi)[/tex]
[tex](r, \theta) = (-r, \theta + (2 + 1)\pi)[/tex]
[tex](r, \theta) = (-r, \theta + 3\pi)[/tex]
[tex](a)\ (2, \frac{5\pi}{6})[/tex]
[tex]r = 2\ \ \ \ \theta = \frac{5\pi}{6}[/tex]
So, the pairs are:
[tex](r, \theta) = (r, \theta + 2\pi)[/tex]
[tex](2, \frac{5\pi}{6}) = (2, \frac{5\pi}{6} + 2\pi)[/tex]
Take LCM
[tex](2, \frac{5\pi}{6}) = (2, \frac{5\pi+12\pi}{6})[/tex]
[tex](2, \frac{5\pi}{6}) = (2, \frac{17\pi}{6})[/tex]
And
[tex](r, \theta) = (-r, \theta + 3\pi)[/tex]
[tex](2, \frac{5\pi}{6}) = (-2, \frac{5\pi}{6} + 3\pi)[/tex]
Take LCM
[tex](2, \frac{5\pi}{6}) = (-2, \frac{5\pi+18\pi}{6})[/tex]
[tex](2, \frac{5\pi}{6}) = (-2, \frac{23\pi}{6})[/tex]
The other pairs are:
[tex](2, \frac{17\pi}{6})[/tex] and [tex](-2, \frac{23\pi}{6})[/tex]
[tex](b)\ (1, -\frac{2\pi}{3})[/tex]
[tex]r = 1\ \ \ \theta = -\frac{2\pi}{3}[/tex]
So, the pairs are:
[tex](r, \theta) = (r, \theta + 2\pi)[/tex]
[tex](1, -\frac{2\pi}{3}) = (1, -\frac{2\pi}{3} + 2\pi)[/tex]
Take LCM
[tex](1, -\frac{2\pi}{3}) = (1, \frac{-2\pi+6\pi}{3})[/tex]
[tex](1, -\frac{2\pi}{3}) = (1, \frac{4\pi}{3})[/tex]
And
[tex](r, \theta) = (-r, \theta + 3\pi)[/tex]
[tex](1, -\frac{2\pi}{3}) = (-1, -\frac{2\pi}{3} + 3\pi)[/tex]
Take LCM
[tex](1, -\frac{2\pi}{3}) = (-1, \frac{-2\pi+9\pi}{3})[/tex]
[tex](1, -\frac{2\pi}{3}) = (-1, \frac{7\pi}{3})[/tex]
The other pairs are:
[tex](1, \frac{4\pi}{3})[/tex] and [tex](-1, \frac{7\pi}{3})[/tex]
[tex](c)\ (-1, \frac{5\pi}{4})[/tex]
[tex]r = -1 \ \ \ \ \theta = \frac{-5\pi}{4}[/tex]
So, the pairs are
[tex](r, \theta) = (r, \theta + 2\pi)[/tex]
[tex](-1, \frac{-5\pi}{4}) = (-1, \frac{-5\pi}{4} + 2\pi)[/tex]
Take LCM
[tex](-1, \frac{-5\pi}{4}) = (-1, \frac{-5\pi+8\pi}{4} )[/tex]
[tex](-1, \frac{-5\pi}{4}) = (-1, \frac{3\pi}{4} )[/tex]
And
[tex](r, \theta) = (-r, \theta + 3\pi)[/tex]
[tex](-1, \frac{-5\pi}{4}) = (-(-1), \frac{-5\pi}{4}+ 3\pi)[/tex]
Take LCM
[tex](-1, \frac{-5\pi}{4}) = (1, \frac{-5\pi+12\pi}{4})[/tex]
[tex](-1, \frac{-5\pi}{4}) = (1, \frac{7\pi}{4})[/tex]
So, the other pairs are:
[tex](-1, \frac{3\pi}{4} )[/tex] and [tex](1, \frac{7\pi}{4})[/tex]
