Q.

If p=cscθ+cotθ and q=1cscθ-cotθ, then which of the following is/are correct

(i) p-q=1(ii) p+q=1(iii) p-q=0(iv) p+q=0

Choose the correct option from the following:

1 (i) and (ii)
 
2 (ii) and (iii)  
3 (iii) and (iv)  
4 (iii) only  

Ans.

(4)

We know, 

csc 2θ-cot 2θ=1cscθ-cotθcscθ+cotθ=1cscθ+cotθ=1cscθ-cotθp=qp-q=0