cosec⁴A-cosec ²A=cot ⁴A-cot ²A




from the internet it's different and i did in in this way :
cosec ²A)²-cosec ²A
1+cot ⁴A-2cot²A-1+cot ²A(1-1=0)(2cot ²A-cot ²A=cot ²A)
cot ⁴A-cot ²A