Construct a circle with a radius of (2) at the origin
The line l will be tangent to this circle
The equation of this circle is
x^2 + y^2 = 4 (1)
The slope of a tangent line to this circle at any point will be -x /y
So
-x/ y = 1
-x = y (2)
Sub (2) into (1)
x^2 + (-x)^2 = 4
2x^2 = 4
x^2 = 2
x = sqrt2
y =-sqrt 2
The equation of the line is
y = 1 (x - sqrt 2) - sqrt 2
y = x - 2sqrt 2
y= x -sqrt 8
When x = 0, y= - sqrt 8
When y = 0 x = sqrt 8
So points (0.-sqrt 8) and (sqrt 8,0) are on the line
The base of the triangle is sqrt [ (sqrt 8)^2 + (-sqrt 8)^2 ] ]= sqrt (16) = 4
Its area is (1/2) base * height = ( 1/2)(4) (2) = 4