Q.If \( \tan \theta = \frac{x}{y} \), then what is the value of \[ \frac{x\sin\theta - y\cos\theta}{x\sin\theta + y\cos\theta}? \] (a) \(\cfrac{x^2+y^2}{x^2-y^2}\) (b) \(\cfrac{x-y}{x+y}\) (c) \(\cfrac{x+y}{x-y}\) (d) \(\cfrac{x^2-y^2}{x^2+y^2}\)
Answer: D
\[ \tan \theta = \frac{x}{y} \\ \Rightarrow \frac{\sin \theta}{\cos \theta} = \frac{x}{y} \\ \Rightarrow \frac{x \sin \theta}{y \cos \theta} = \frac{x^2}{y^2} \\ \Rightarrow \frac{x \sin \theta + y \cos \theta}{x \sin \theta - y \cos \theta} = \frac{x^2 + y^2}{x^2 - y^2} \\ \Rightarrow \frac{x \sin \theta - y \cos \theta}{x \sin \theta + y \cos \theta} = \frac{x^2 - y^2}{x^2 + y^2} \]
Similar Questions