Answers

2014-04-01T15:59:59+05:30
2sec²Ф-sec⁴Ф-2cosec²Ф+cosec⁴Ф =cos⁴Ф-tan⁴Ф
RHS =
2sec²Ф-sec⁴Ф-2cosec²Ф+cosec⁴Ф
=2(1+tan²Ф) −(1+tan²Ф)² −2(1+cot²Ф)+(1+cot²Ф)² 
=2(1+tan²Ф) −(1+tan⁴Ф+2tan²Ф) −2(1+cot²Ф)+(1+cot⁴Ф+2cot²Ф)
=2+2tan²Ф) −1−tan⁴Ф−2tan²Ф −2−2cot²Ф+1+cot⁴Ф+2cot²Ф
=2−2−1+1 +2tan²Ф −2tan²Ф −tan⁴Ф−2cot²Ф+2cot²Ф+cot⁴Ф
= −tan⁴Ф+cot⁴Ф
=cot⁴Ф−tan⁴Ф

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