(See diagram) The gradient of the line joining the origin to the point A is 1/2. The distance between A and the origin is sqrt 2205. What are the coordinates of A?

(42, 21) or (–42, –21)

Step-by-step explanation:

let A(x, y), A on line 2y = x

distance

x² + y² = 2205

(2y)² + y² = 2205

y² = 441

y = ±21

x = ±42

step-by-step explanation:

we have

using a graphing tool

see the attached figure

this is a quadratic equation (vertical parabola) open up

the vertex is a > vertex

the domain of the function is all real > interval (-∞,∞)

the range of the function is the > [-6.125,∞)

the function has two x->   and

the function is increasing over the > (0.25,∞)

the function is decreasing over the > (-∞,0.25)