Can you help me find the rectangular coordinates of each point (5,pi/4) (-2,pi/6) (-1,2pi/3)
I'm assuming each point is in polar form (r,theta)
Yes they are
You can use these formulas x = r*cos(theta) y = r*sin(theta) make sure you are in radian mode
so 5*cos(theta) and pi/4*sin(theta)
(r,theta) = (5,pi/4) so r = 5 theta = pi/4
x = r*cos(theta) = 5*cos(pi/4) = ?? y = r*sin(theta) = 5*sin(pi/4) = ??
(3.54, 3.54)
\(\large \begin{array}{cccllll} 5&,&(\frac{\pi}{4})\\ r&&\theta \end{array}\qquad \begin{cases} x=rcos(\theta)\\ y=rsin(\theta) \end{cases}\qquad \begin{array}{cccllll} x&,& y\\ \uparrow &&\uparrow \\ rcos(\theta)&&rsin(\theta) \end{array}\)
since \[\Large \cos\left(\frac{\pi}{4}\right) = \frac{\sqrt{2}}{2}\] and \[\Large \sin\left(\frac{\pi}{4}\right) = \frac{\sqrt{2}}{2}\] this means \[\Large (x,y) = \left(\frac{5\sqrt{2}}{2},\frac{5\sqrt{2}}{2}\right)\]
that is the exact form, but the approximate form works as well
ok thanks!
np
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