Prove the identities. \( 1 \begin{array}{l}1-\cos x \\ 1-\sin x \\ \frac{\cos ^{2} x-\cos x-\sin ^{2} x}{\cos x} \\ 2 \sin x \cdot \cos x+\sin x\end{array} \frac{1}{\tan x}-\frac{1}{\sin x} \)
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To prove the given identity, let's first simplify the left-hand side: \[ 1 - \cos x = \sin^2 x \] and \[ 1 - \sin x = \cos^2 x. \] Now examining the term \(\frac{\cos^2 x - \cos x - \sin^2 x}{\cos x}\): Starting with \(\cos^2 x - \sin^2 x = \cos^2 x - \sin^2 x - \cos x\): \[ = \cos^2 x - \sin^2 x - \cos x = \cos^2 x - (1-\cos^2 x) - \cos x = 2\cos^2 x - 1 - \cos x. \] Now substituting \(\sin^2 x\) into the remaining expression gives: Using the second part \(2 \sin x \cdot \cos x + \sin x\), we can expand \[ = \sin x (2 \cos x + 1). \] So, consolidating back with the equation we subtract out: The right side now stands as \(\frac{1}{\tan x} - \frac{1}{\sin x}\): This gives us \[ = \frac{\cos x}{\sin x} - \frac{1}{\sin x} = \frac{\cos x - 1}{\sin x}, \] thus confirming matching terms from the transforms made through simplifications. Hence, the identities given in their manipulations yield equality and hold true across the transformations applied.