#tanx + cotx = 2#
#tanx + 1/tanx = 2#
#tan^2x/(tanx) + 1/tanx = 2#
#(tan^2x + 1)/(tanx) = 2#
#tan^2x + 1 = 2tanx#
#tan^2x - 2tanx + 1 = 0#
let #a = tanx#
#a^2 - 2a + 1 = 0#
#(a-1)^2 = 0#
#a - 1 = 0#
#tanx - 1 = 0#
#tanx = 1#
#x = tan^-1(1) #
#x = 45# degrees.
#sinx#
#= sin45#
#= 1/sqrt(2)#