What is the value of (secA + tanA - 1) (secA - tanA + 1) ?
Answer & explanation
Correct answer: option 3
(secA + tanA - 1) (secA - tanA + 1)
= sec²A - ( tanA - 1 )²
= sec²A - tan²A - 1 + 2tanA
{ using , sec²A - tan²A = 1 }
= 1 - 1 + 2tanA
= 2tanA
What is the value of (secA + tanA - 1) (secA - tanA + 1) ?
Correct answer: option 3
(secA + tanA - 1) (secA - tanA + 1)
= sec²A - ( tanA - 1 )²
= sec²A - tan²A - 1 + 2tanA
{ using , sec²A - tan²A = 1 }
= 1 - 1 + 2tanA
= 2tanA