# The Excel Circle Challenge

#### Stanley Gould

The following formula solution request will be used within a High School students Math class challenge problem.

The general problem is to create one formula that combines the Unit-Circle (radius = 1) equation (x^2+y^2 = 1) and the Slope Intercept equation for a line segment (y = mx+b).

The problem space is inside of a unit-circle's first (45-degrees) octant (note - all x and y coordinates have positive values, within or upon the edges of the octant).

Formula #1 - calculate a line segment (whose slope is '2') terminal coordinates on the circle's circumference, and its origin coordinate is x=0 (y-intercept is 0) and y is given as: 0<y<1.

Formula #2 - calculate a line segment (whose slope is '1'), terminal coordinates on the circle's circumference, and its origin coordinate 'x' is given as 0<x<1, and its origin coordinate 'y' is given as: 0<y<1.

Optional Excel Function Code - if you are familiar with Excel VBA coding, this formula needs to be converted into an Excel VBA function statement. before students can use this. Your help would be greatly appreciated.

My request is to receive the two formulas (#1 & #2), which are intended to compute each line segment's terminal coordinates, with the line slope values included within the formulas, as constants. The formula will produce the terminal x,y coordinates for each line segment. Thank you.

#### skipjack

Forum Staff
On each edge of the first octant, at least one point has 0 as its x-coordinate and at least one poiint has 0 as its y-coordinate, so it doesn't make sense to specify "all x and y coordinates have positive values, within or upon the edges of the octant".