` (sin^(4) theta - cos^(4)theta +1) "cosec"^(2) theta` का मान क्या होगा ?

Options

A. `-2`
B. 0
C. 1
D. 2

Answer

d

Explanation

` (sin^(4)theta - cos ^(4) theta+1) * cosec^(2)theta`
` = {(sin^(2)theta- cos^(2)theta)(sin^(2)theta+cos^(2)theta)+1} `
` *cosec^(2)theta`
` = { (sin^(2) theta- cos^(2)theta)*1+1} *cosec^(2)theta`
` = {(sin^(2) theta - cos^(2) theta)+1}*cosec^(2)theta`
` = {sin^(2) theta - n( 1 - sin^(2) theta)+1}*cosec^(2)theta`
` = { 2 sin^(2) theta }*1/(sin^(2)theta)=2`