Complete the trigonometric identity.
cot(-u)=

Hello :
cot(-u)= cos(-u)/sin(-u)
           = cos(u)/(-si(u))  because : cos(-u) = cos(u)   and sin(-u) = - sin(u)
           = -(cos(u)/si(u))
cot(-u) = -cot(u)

Then why is the question on here if you know the answer