If secA + tanA = x, express secA in terms of x.
Show answer & explanation
Correct answer: A
Explanation
Given,
secA + tanA = x
(secA + tanA)(secA − tanA) = x(secA − tanA)
1 = x(secA − tanA)
secA − tanA = 1/x
(secA + tanA) + (secA − tanA) = x + 1/x
2secA = x + 1/x
secA = (x + 1/x)/2 = (x² + 1)/2x