We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website.
Please click on "Accept cookies" if you agree to the setting of cookies. Cookies that do not require consent remain unaffected by this, see
cookie policy and privacy policy.
DECLINE COOKIES

Find the intersection between graph r=1 and r=2cosθ

i did cosθ= 1/2

cos^-1 1/2 = 1/3π (radiance)

from here on ward i was told to add something to this which should give me 5/3π

and thus my 2 intersection should be

(1, 1/3π) (1, 5/3π)

please tell me what i do in order to get to 5/3π

YEEEEEET Feb 27, 2019

#1**+2 **

Set the r's equal and we have that

2cos θ = 1 divide both sides by 2

cos θ = 1/2

arccos (1/2) = θ

Remember that arccos has a range of [-pi,2, pi/2 ]

Note that this happens at pi/3 and at -pi/3 = 5pi/3 if we are on the interval [0, 2pi ]

So...the intersection points are

(r, θ) = ( 1, pi/3) and (1, 5pi/3 )

CPhill Feb 27, 2019