Derivative of Tan(X) \frac{d}{dx}Tan(X)=\frac{d}{dx} (\frac{Sin(x)}{Cos(x)}) Sin(x)=\frac{e^{ix} – e^{-ix}}{2i} Cos(x)=\frac{e^{ix} + e^{-ix}}{2} \frac{e^{ix} – e^{-ix}}{2i} \frac {2}{e^{ix} + e^{-ix}} Cancel the 2s \frac{e^{ix} – e^{-ix}}{i} \frac {1}{e^{ix} + e^{-ix}} Multiply by \frac{i}{i} to clear the i from the denominator \frac{e^{ix} – e^{-ix}}{i} \frac {1}{e^{ix} + e^{-ix}} \frac {i}{i} i * i = -1 -i * \frac {d}{dx} ( \frac {e^{ix} – e^{-ix}} {e^{ix} + e^{-ix}} ) f(x) = e^{ix} – e^{-ix} g(x) = e^{ix} + e^{-ix} -i *\frac{g(x) \frac{d}{dx} f(x) – f(x) \frac{d}{dx} g(x)}{( g(x) )^2} Start by solving the top of the equation. -i * g(x) \frac{d}{dx} f(x) – f(x) \frac{d}{dx} g(x) -i * [ ( e^{ix} + e^{-ix} ) ( i * e^{ix} + i * e^{-ix} ) ] – [ ( e^{ix} – e^{-ix} ) ( i * e^{ix} – i * e^{-ix} ) ] -i * [ i * e^{2ix} + i + i + e^{-2ix} ] – [ i * e^{2ix} – i – i +e^{-2ix} ] expand – through right side of equation -i * [ i * e^{2ix} + (2 * i) + e^{-2ix} – i * e^{2ix} + (2 * i ) – e^{-2ix} ] -i * [ 4 * i ] top half = 4 bottom half of equation is ( e^{ix} + e^{-ix}) ( e^{ix} + e^{-ix}) e^{2ix} + i + i + e^{-2ix} Final Bottom Answer is: e^{2ix}+( 2 * i ) + e^{-2ix} Final answer \frac{4}{e^{2ix}+( 2 * i ) + e^{-2ix}} Break down d/dx Tan(x) \frac{d}{dx} Tan(x) = \frac{4}{e^{2ix} + ( 2 * i ) + e^{-2ix}} \frac{d}{dx} Tan(x) = \frac{1}{cos^2(x)} \frac{1}{cos^2(x)} = \frac{2^{2}}{( e^{ix} + e^{-ix} ) ^{2}} \frac{1}{ cos^{2}(x) } = sec^{2}(x) = \frac{4}{e^{2ix} + ( 2 * i ) + e^{-2ix}}