finding parametric representation of half circle

i have a curve from(-2,0) to (2,0) half circle

how to find the formula for x
and y
?

i know that its some sort of trigonometric expression

Quote:

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Originally Posted by transgalactic

i have a curve from(-2,0) to (2,0) half circle

how to find the formula for x
and y
?

i know that its some sort of trigonometric expression

---

At the level you're studying at you're expected to know this.

x = 2 cos(t)
y = 2 sin(t)

The domain of t is left for you to find.

x=R*cos(t)
y=R*sin(t)

{IT BECAUSE x^2+y^2=R^2 describes a circle}
R is the radius. (R=2 in your case)

t-is angle.

Now, in your opinion which restriction should be on t to get half circle?

t from 0 to pi
thanks
:)