pre cal prob

February 2nd, 2011 @7:27 am

Remember the distance formula, based on the pythagorean theorem?

If you have a horizontal distance x and a vertical distance y, then the hypotenuse will be x² + y²

So your formula is x² + y² = 2²

or

x² + y² = 4

Or solving in terms of y:

y² = 4 – x²

y = sqrt(4 – x²)

February 2nd, 2011 @8:05 am

pythagoras’ theorem

c^2 = a^2 + b^2

4 = x^2 + y^2

x^2 + y^2 – 4 = 0

y^2 = 4 – x^2

y = sqrt(4 – x^2)

x ² + y ² = 2 ²

x ² + y ² = 4

(the equation of a circle centre O , radius 2)