equation of semi circle

**arturdo968** · September 22nd 2008, 04:13 PM

what is the equation of a semi circle with:

-diameter of 6
-amplitude of 3
-starting at the x-axis
-the center is at (5,0)

and what is the generic equation of a semi circle?
thank you

**11rdc11** · September 22nd 2008, 04:30 PM

Put your info into the standard equation of a circle

$\frac{(x-5)^2}{9} + \frac{y^2}{9} =1$

and then solve for y and that will give you the equation to a semi circle

$y = \pm \sqrt{9-(x-5)^2}$

**arturdo968** · September 22nd 2008, 04:34 PM

what is the first formula that you showed? i'm not familiar with it

**11rdc11** · September 22nd 2008, 04:41 PM

$(x-a)^2 + (y-b)^2 = r^2$

a and being your center points respectively (5,0)

**arturdo968** · September 22nd 2008, 04:50 PM

oh ok i see it now. sorry, thank you very much though, that helped me out. do you by anychance know how to set restrictions on lines so that it only graphs a segment?

**11rdc11** · September 22nd 2008, 05:23 PM

Nope but when you find out let me know to please. Still haven't figured out how to do it on my TI89

**arturdo968** · September 22nd 2008, 05:30 PM

that's exactly what i'm trying to figure out. i'm trying to find the way to set up a domain and range on it and i still can't lol. i'll make sure to tell you if i find something. this is for a project due thursday =p

**bkarpuz** · September 23rd 2008, 09:01 AM

In parametric form, you may let $\cos(t)=\frac{x-5}{3}$ and $\sin(t)=\frac{y}{3}$ to get $\alpha(t)=(x(t),y(t))=(3\cos(t)+5,\sin(t))$ for $t\in[0,\pi]$ .

Thread: equation of semi circle

LinkBack

Thread Tools

Display

equation of semi circle

Similar Math Help Forum Discussions

semi circle question

centre semi circle

Semi-circle function

Help me Finding semi circle

A semi-circle in a square.

Search Tags