Verify the following: tan( a + p/2) = -cot a

a= alpha and p= pie since I do not have that button.

LS = tan(a + π/2)

= sin(a+π/2)/cos(a+π/2)
= (sinacosπ/2 + cosasinπ/2)/(cosacosπ/2 - sinasinπ/2)
= 0 + cosa)/0-sina)
= cosa/-sina
= - cota