Question
In the following match each item given under the $\text{column}\ C_1$ to its correct answer given under the $\text{column}\ C_2$:
| $\text{column}\ C_1$ | $\text{column}\ C_2$ | ||
| $(a)$ | $\sin(\text{x + y})\sin\text{x}-\text{y}$ | $(i)$ | $\cos^2\text{x}-\sin^2\text{y}$ |
| $(b)$ | $\cos(\text{x + y})\cos(\text{x}-\text{y})$ | $(ii)$ | $\frac{1-\tan\theta}{1+\tan\theta}$ |
| $(c)$ | $\cot\Big(\frac{\pi}{4}+\theta\Big)$ | $(iii)$ | $\frac{1+\tan\theta}{1-\tan\theta}$ |
| $(d)$ | $\tan\Big(\frac{\pi}{4}+\theta\Big)$ | $(iv)$ | $\sin^2\text{x}-\sin^2\text{y}$ |
