1-1/w=20/w^2

Solution for 1-1/w=20/w^2 equation:

D( w )

w^2 = 0

w = 0

w^2 = 0

w^2 = 0

1*w^2 = 0 // : 1

w^2 = 0

w = 0

w = 0

w = 0

w in (-oo:0) U (0:+oo)

1-(1/w) = 20/(w^2) // - 20/(w^2)

1-(1/w)-(20/(w^2)) = 0

1-w^-1-20*w^-2 = 0

t_1 = w^-1

1-20*t_1^2-1*t_1^1 = 0

1-20*t_1^2-t_1 = 0

DELTA = (-1)^2-(-20*1*4)

DELTA = 81

DELTA > 0

t_1 = (81^(1/2)+1)/(-20*2) or t_1 = (1-81^(1/2))/(-20*2)

t_1 = -1/4 or t_1 = 1/5

t_1 = -1/4

w^-1+1/4 = 0

1*w^-1 = -1/4 // : 1

w^-1 = -1/4

-1 < 0

1/(w^1) = -1/4 // * w^1

1 = -1/4*w^1 // : -1/4

-4 = w^1

w = -4

t_1 = 1/5

w^-1-1/5 = 0

1*w^-1 = 1/5 // : 1

w^-1 = 1/5

-1 < 0

1/(w^1) = 1/5 // * w^1

1 = 1/5*w^1 // : 1/5

5 = w^1

w = 5

w in { -4, 5 }