Mathematics
15 Online
OpenStudy (babynini):
convert the equation to polar form
x^2-y^2=7
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (babynini):
(use variables r and theta as needed)
OpenStudy (babynini):
@jim_thompson5910 :)
OpenStudy (alekos):
substitute x=rcosθ and y=rsinθ
OpenStudy (babynini):
and that would be the final answer?
OpenStudy (babynini):
\[(rcos \theta)^2- (rsin \theta)^2=7\]
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (babynini):
@alekos
OpenStudy (alekos):
No, I would go further
\[r^{2}(\cos ^{2}\theta-\sin ^{2}\theta)=7\]
OpenStudy (alekos):
and the trig identity can now be simplified
OpenStudy (babynini):
\[r^2(\cos^2 \theta) = 7\]
OpenStudy (alekos):
no way. what is cos2θ ?
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (babynini):
haha oops sorry I means cos2theta
OpenStudy (babynini):
\[r^2(\cos2 \theta) = 7\]
OpenStudy (alekos):
very good and now we can go further
\[r ^{2}=7\sec2\theta \]
OpenStudy (babynini):
hmm I just need to write it in polar form. Should we be going this far?
OpenStudy (babynini):
did you mean cos?
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (babynini):
oo I see what you did, okay, nevermind.
OpenStudy (alekos):
we are heading to the final polar form
OpenStudy (alekos):
just take the square root of both sides and you have the final polar form
OpenStudy (babynini):
\[r=\sqrt{7\sec2 \theta}\]
OpenStudy (alekos):
beautiful. thats it!
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (babynini):
yay! thank you :)
OpenStudy (babynini):
hrmm they don't like that answer -.-
OpenStudy (babynini):
@Miracrown
OpenStudy (babynini):
oh, I figured it out :)
they wanted
r^2(cos2theta)=7