Recall {{MATH_83}} means that {{MATH_84}} and {{MATH_85}} with {{MATH_86}}. Implicitly differentiating with respect {{MATH_87}} we see {{ENV_88}} While {{MATH_89}}, we need our answer written in terms of {{MATH_90}}. Since we are assuming that {{MATH_91}} we may consider the following triangle: {{CMD_92}} {{ENV_93}} {{CMD_94}} We may now scale this triangle by a factor of {{MATH_95}} to place it on the unit circle: {{CMD_96}} {{ENV_97}} {{CMD_98}} From the unit circle above, we see that {{ENV_99}} To be completely explicit, {{MATH_100}} {{CMD_101}} {{CMD_102}}