Eliminate the parameter

X=2cos t
Y=1+sint

Question

Eliminate the parameter 

X=2cos t
Y=1+sint

cazeh · Answer

cos(t) = x/2 

cos^2(t) = x^2/4 

Now do something similar with y. Then add them up. The sum is 1

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marcelie · Answer

Oops..  Suppose to be theta lol

mathmale · Answer

An alternative approach:

X=2cos t
Y=1+sint

Solve the first equation for cos t and the second for sin t.
Now square both sides of both equations.
Note that 

$$\sin ^{2}x+\cos ^{2}x=1$$

mathmale · Answer

This fact will enable you to eliminate the trig functions and be left with a relationship in x and y only.

marcelie · Answer

(x/2)^2+ (y-1)^2=1

marcelie · Answer

This is where i get lost

marcelie · Answer

@mathmale

marcelie · Answer

@cazeh

cazeh · Answer

it is hard i cant help sry dude :d

marcelie · Answer

Lol okay

dumbcow · Answer

(x/2)^2 = x^2 / 4

$$(y-1)^2 = 1 - \frac{x^2}{4}$$
convert to 1 fraction
$$(y-1)^2 = \frac{4-x^2}{4}$$
take sqrt
$$y-1 = \frac{\pm \sqrt{4-x^2}}{2}$$
$$y = 1 \pm \frac{\sqrt{4-x^2}}{2}$$

marcelie · Answer

Oh could  we actually  do that to eliminate  the parameter?