How do you prove (secA - 1) / (sin^2A) = (sec^2A) / (1 + secA)secA1sin2A=sec2A1+secA?

2 Answers
Mar 15, 2018

To prove,we take
sec^2A-1=tan^2A,andtanA=sinA/cosA,1/cosA=secAsec2A1=tan2A,andtanA=sinAcosA,1cosA=secA

Explanation:

(secA-1)/sin^2A=sec^2A/(1+secA)secA1sin2A=sec2A1+secA
LHS=(secA-1)/sin^2A=((secA-1)(secA+1))/((sin^2A)(secA+1))LHS=secA1sin2A=(secA1)(secA+1)(sin2A)(secA+1)
=(sec^2A-1)/((sin^2A)(secA+1))=tan^2A/(sin^2A(secA+1))=(sin^2A/cos^2A)/(sin^2A(secA+1))=(1/cos^2A)/(secA+1)=sec^2A/(1+secA)=RHS=sec2A1(sin2A)(secA+1)=tan2Asin2A(secA+1)=sin2Acos2Asin2A(secA+1)=1cos2AsecA+1=sec2A1+secA=RHS

Mar 17, 2018

Kindly refer to a Proof in the Explanation.

Explanation:

We have, sec^2A-1=tan^2A=sin^2A*1/cos^2Asec2A1=tan2A=sin2A1cos2A.

:. (secA+1)(secA-1)=sin^2A*sec^2A.

rArr (secA-1)/sin^2A=sec^2A/(1+secA, as desired!