Question
Derive the identity. Check using a graphing calculator.$$\frac{\sin (\alpha+\beta)}{\cos (\alpha-\beta)}=\frac{\tan \alpha+\tan \beta}{1+\tan \alpha \tan \beta}$$
Step 1
Step 1: We start with the left-hand side of the equation and expand the sine and cosine of the sum and difference of two angles using the sum-to-product identities: $$\frac{\sin (\alpha+\beta)}{\cos (\alpha-\beta)}=\frac{\sin \alpha \cos \beta + \cos \alpha \sin Show more…
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