# Differential

Calculus Level 4

Let $$x= \ln \tan \dfrac \theta2$$ and given that $$y= \tan \theta - \theta$$. Determined $$\frac{{d}^{2}y}{dx^{2}}$$ if can be expressed in the form $$A \tan B\theta . C \sin D\theta(E \sec^{F} G\theta+H)$$. Compute $$A+B+C+D+F+G+H$$.

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