Question
If 2x = cosec @ and 4/x = cot @ then the value of 2(x ²
- 1/x ² ) isSolution
2x = cosec@ .............(i) 2/x = cot @ ...............(ii) adding (i) and (ii), we get 2 (x + 1/x) = cosec @ + cot @ ...........(iii) subtracting (ii) from (i), we get 2 (x - 1/x) = cosec @ - cot @ ..............(iv) Multiply (iii) and (iv), we get 4 (x 2  - 1/x2) = cosec2  @ - cot 2  @ 2(x2  - 1/x2  ) = 1/2Â
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