Question

Prove that
1/(sec A - tan A) =sec A + tan A​

Answer 1

Explanation:

let s estimate the following

`(secA-tanA)(secA+tanA)=sec^2A-tan^2A=(1)/(cos^2A)-(sin^2A)/(cos^2A)=(1-sin^2A)/(cos^2A)=(cos^2A)/(cos^2A)=1`

as
`cos^2A+sin^2A=1`

it means that

`(1)/(secA-tanA)=secA+tanA`

hope this helps