Ask your own question, for FREE!
Mathematics 15 Online
OpenStudy (anonymous):

[

OpenStudy (jdoe0001):

\(\large \begin{array}{lllcc} &&&x&y\\ &&rectangular&-1,& \sqrt{3}\\ &&&x&y\\ &&polar&r,& \theta\\ \quad \\ \quad \\ r^2 = x^2 + y^2 \implies r = \sqrt{x^2 + y^2}\\ \quad \\ \theta = tan^{-1}\left(tan\left(\cfrac{y}{x}\right)\right) \end{array}\)

OpenStudy (jdoe0001):

so, what do you get for "r"?

OpenStudy (anonymous):

sq rt 10?

OpenStudy (anonymous):

and theta 6.14?

OpenStudy (jdoe0001):

hmm... I should correct that \(\bf r^2 = x^2 + y^2 \implies r = \sqrt{x^2 + y^2}\\ \quad \\ tan(\theta) = \cfrac{y}{x} \implies \theta = tan^{-1}\left(\cfrac{y}{x}\right)\)

OpenStudy (anonymous):

same for r, theta -1.04?

OpenStudy (jdoe0001):

\(\bf r = \sqrt{(-1)^2+(\sqrt{3})^2} \implies r = \sqrt{(-1)^2+(\sqrt{3^2})} \implies r = \sqrt{1+3}\)

OpenStudy (anonymous):

r=2..

OpenStudy (jdoe0001):

yeap, so r = 2, and \(\bf \theta = tan^{-1}\left(\cfrac{y}{x}\right) \implies \theta = tan^{-1}\left(\cfrac{\sqrt{3}}{-1}\right) \implies \theta = tan^{-1}\left(-\sqrt{3}\right)\)

OpenStudy (jdoe0001):

if you check your Unit Circle, that angle is there :)

OpenStudy (anonymous):

negative sq rt 3 is on the unit circle?

OpenStudy (jdoe0001):

well, anyhow, lemme make it ... this way one sec

OpenStudy (jdoe0001):

\(\bf tan(\theta)= \cfrac{sin(\theta)}{cos(\theta)}\\ \quad \\ \quad \\ sin(\theta) = -\cfrac{\sqrt{3}}{2}\qquad\qquad cos(\theta) = \cfrac{1}{2}\\\quad \\ \quad \\ tan(\theta) = \cfrac{-\frac{\sqrt{3}}{2}}{\frac{1}{2}} \implies -\cfrac{\sqrt{3}}{\cancel{2}} \times \cfrac{\cancel{2}}{1} \implies -\sqrt{3}\)

OpenStudy (jdoe0001):

do you see now the angle where \(\bf sin(\theta) = -\cfrac{\sqrt{3}}{2}\qquad\qquad cos(\theta) = \cfrac{1}{2}\)

OpenStudy (anonymous):

300 degrees of 5pi/3?

OpenStudy (anonymous):

or*

OpenStudy (jdoe0001):

yeap, at 5pi/3 tangent is \(\bf -\sqrt{3}\)

OpenStudy (anonymous):

so that makes the coordinates 2, 300?

OpenStudy (jdoe0001):

keep in mind that, I could have gotten also angle at \(\bf \cfrac{2\pi}{3}\) and that one also has a tangent of \(\bf -\sqrt{3}\) however it would be OUTSIDE THE RANGE of the \(\bf tan^{-1}\) function since the arcTangent function range is between \(\bf -\cfrac{\pi}{2}\ and \ \cfrac{\pi}{2}\)

OpenStudy (jdoe0001):

yes, the polar coordinates will be \(\bf (2, 300^o) \ or \ \left(2, \cfrac{5\pi}{3}\right)\)

OpenStudy (anonymous):

cool thanks.

OpenStudy (jdoe0001):

yw

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!