- two *(tan(x) - (tan(x)^ two + one)/(tan(x) - one))*(tan(x)^ two + one)/(tan(x) - one)^ two = zero
minus 2 multiply by ( tangent of (x) minus ( tangent of (x) squared plus 1) divide by ( tangent of (x) minus 1)) multiply by ( tangent of (x) squared plus 1) divide by ( tangent of (x) minus 1) squared equally 0
minus two multiply by ( tangent of (x) minus ( tangent of (x) to the power of two plus one) divide by ( tangent of (x) minus one)) multiply by ( tangent of (x) to the power of two plus one) divide by ( tangent of (x) minus one) to the power of two equally zero