Find the point in the first quadrant where the line y = 2 x intersects a circle of radius 4 centered at the origin.

Question

word problem

Answer 1

y = 2x

x² + y² = 16

 

x² + (2x)² = 16

 

5x² = 16

 

In first quadrant,

 

x = +√(16/5) = 4/√5 = (4√5)/5

y = 2x = 2(4√5)/5 = (8√5)/5