**Solution:**

**(i)** It is not true, in general. This relation is true for some particular values of A and B.

For example, if A = 0 and B = 90,

Then, Sin (A+B) = sin (0+90) = sin 90 = 1

And, sin A + sin B = sin 0 + sin 90 = 0 + 1 = 1

Hence, sin (A+B) = sin A + sin B

**(ii) **True.

sin 0° = 0

sin 30° = 1/2

sin 45° = 1/√2

sin 60° = √3/2

sin 90° = 1

Thus the value of sin θ increases as θ increases.

**(iii)** False.

cos 0° = 1

cos 30° = √3/2

cos 45° = 1/√2

cos 60° = 1/2

cos 90° = 0

Thus the value of cos θ decreases as θ increases.

**(iv)** True.

cot A = cos A/sin A

cot 0° = cos 0°/sin 0° = 1/0 = undefined