If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( w )
w = 0
w = 0
w = 0
w in (-oo:0) U (0:+oo)
2*w = 40/w // - 40/w
2*w-(40/w) = 0
2*w-40*w^-1 = 0
2*w^1-40*w^-1 = 0
(2*w^2-40*w^0)/(w^1) = 0 // * w^2
w^1*(2*w^2-40*w^0) = 0
w^1
2*w^2-40 = 0
2*w^2-40 = 0
DELTA = 0^2-(-40*2*4)
DELTA = 320
DELTA > 0
w = (320^(1/2)+0)/(2*2) or w = (0-320^(1/2))/(2*2)
w = 2*5^(1/2) or w = -2*5^(1/2)
w in { -2*5^(1/2), 2*5^(1/2)}
w in { -2*5^(1/2), 2*5^(1/2) }
| 12x-5x=2x-7 | | (xy^2)(7xyz)= | | (a-3)x^2+11x+a^2-9=0 | | x/3=-10/3 | | f(x+6)=9x-6 | | x-0.7x=180 | | 7(6y-7)= | | 4-4x^2-12=0 | | -6a(-9)+(-4a)+28= | | -2x^3y-2x^2y+24xy=0 | | r/2=-5 | | a^2+2a-32=0 | | 34-6x=7-9x | | -56=-8a | | 15+0.10=20+0.5 | | 17-3h=35 | | 13x+17=x | | -10=a/5 | | 3p-pq+4pr= | | N/-5=4-(-9) | | 5x+-(x-3)=x+6 | | -28=4n | | q^2-12q+11=0 | | (4x-5)(7x^2-7x+9)= | | 1+10x=-8+x | | 100+100=4x+4x | | F(n)=f(n-1)+4 | | -2a-4a+7b-4b= | | 2(50-x)=7(x-41) | | 2y-18=-24-8y | | 4x/3-16=0 | | -5=v+3 |