Question

cot(A+45)-tan(A-45)=2cos2A/1+sin2A​

Answer 1

RHs

cot(A+45)- tan( A-45)

={cos(A+45)×cos(A-45) - sin(A-45)×sin(A+45)}/{sin(A+45)cos(A-45)}

= cos(A+45+A-45)/ {sinA/√2+cosA/√2}^2

= cos2A/sin^2A/2+ cos^2A/2+ 2sinAcosA/2

= 2cos2A/1+2sinAcosA

= 2cos2A/1+sin2A