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Since the line passes through the origin, its equation will be like: y = mx

(m = slope of the line)

Angle made by line y = 0.2x will be tan^{-1}0.2.

Angle made by required line = twice of above angle = 2tan^{-1}0.2

Slope of our line = tan(theta) = tan(2tan^{-1}0.2).

Using the property tan2x = 2tanx / (1 - tan^{2}x):

slope = 2tan(tan^{-1}0.2) / (1- tan^{2}(tan^{-1}0.2) )

Now using the property: tan(tan^{-1}x) = x.

slope = 2(0.2) / (1 - 0.2^{2})

= 0.4 / 0.96

= 0.416

Therefore, Equation of our required line: **y = 0.416x**