Convert r=8cos⁡θ+2sin⁡θ to rectangular equation

Convert

r

=

8

cos

θ

−

2

sin

θ

to Cartesian form

#x^2 + y^2 - 8 x +2 y = 0, using

r

=

√

x

2

+

y

2

≥

0

and

(

x

,

y

)

=

r

(

cos

θ

,

sin

θ

)

.

The Socratic graph of this circle,

with center at

(

4

,

−

1

)

and radius

√

17

.

is immediate.

graph{(x^2+y^2-8x+2y)((x-4)^2+(y+1)^2-0.04)=0[-1 23 -6 6] }

pay attention in your classes and concentrate the best thing you can do to raise your test scores is to pay attention when you're supposed to be learning the material: in class!

take good notes.

do your homework.

use mnemonics and other tricks.

do practice tests.

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