Semi circle formulas (1 Viewer)

[Gavvvvvin]

Okay i know what the formula is for a semi circle above and below the x - axis, but what is the formula for semi cirlces and the left and right hand sides of the y - axis?

 

[Xayma]

x=± √ (r²-y²)

Plus or minus depending on the side you want.

 

[Gavvvvvin]

Okay thanks for that, but can you tell me what shape the graph of x = √x^2 - r^2 is?

 

[Xayma]

Do you mean x=√(y²-r²)

 

[Gavvvvvin]

Do you mean x=√(y²-r²)

woops i meant y=√(x²-r²)

 

[Xayma]

Well the graph of y=√(x²-r²) with r=1 looks like:

 

[Gavvvvvin]

Well the graph of y=√(x²-r²) with r=1 looks like:

Okay i wasnt expecting it to look like that =P

 

[Xayma]

Okay i wasnt expecting it to look like that =P

Why not, x ≥ r so that y remains real, and y doesnt increase as fast as x so it ends up as curved.

 

[da_butterfree]

are we really supposed to know stuff about locus in circles and stuff??
we havent done it yet in class!!!
i dont like locus at all.. and i dont know how to be doing this bit..
any ideas?