Question

Cot4 - 1= cosec4 - 2cosec2​

Answer 1

Solution

Solving RHS, We get,

$cosec {}^{4} a - 2cosec {}^{2}$

$=> cosec {}^{4} a - 2cosec {}^{2} + 1 - 1$

$=>(cosec {}^{2} a - 1) {}^{2} - 1$

$=>(cot {}^{2} a) {}^{2} - 1 = lhs$

Answer 2

Solving RHS, We get,

cosec⁴a − 2cosec²

=> cosec⁴a − 2cosec² + 1 − 1

=> (cosec²a − 1)² − 1

=> (cot²a)² − 1 = LHS