Given cscx-sinx=acscx−sinx=a
=>1/sinx-sinx=a⇒1sinx−sinx=a
=>(1-sin^2x)/sinx=a⇒1−sin2xsinx=a
=>cos^2x/sinx=a⇒cos2xsinx=a
Again secx-cosx=bsecx−cosx=b
=>1/cosx-cosx=b⇒1cosx−cosx=b
=>(1-cos^2x)/cosx=b⇒1−cos2xcosx=b
=>sin^2x/cosx=b⇒sin2xcosx=b
Now a^2b^2(a^2+b^2+3)a2b2(a2+b2+3)
=cos^4x/sin^2x xxsin^4x/cos^2x(cos^4x/sin^2x+sin^4x/cos^2x+3)=cos4xsin2x×sin4xcos2x(cos4xsin2x+sin4xcos2x+3)
=sin^2x xxcos^2x((cos^6x+sin^6x)/(sin^2xcos^2x)+3)=sin2x×cos2x(cos6x+sin6xsin2xcos2x+3)
=cos^6x+sin^6x+3sin^2xcos^2x=cos6x+sin6x+3sin2xcos2x
=(sin^2x)^3+(cos^2x)^3+3sin^2xcos^2x(sin^2x+cos^2x)=(sin2x)3+(cos2x)3+3sin2xcos2x(sin2x+cos2x)
=(sin^2x+cos^2x)^3=1^3=1=(sin2x+cos2x)3=13=1
Proved