3.5 Trigonometry (A-level only)

Prove that:

a.

$sec⁡4A−tan⁡4A≡2sec⁡2A−1\sec^4 A - \tan^4 A \equiv 2\sec^2 A - 1$

[2]

b.

Hence solve, for $\leq A \leq 360$ , the equation,

sec^4 A - \tan^4 A = 3

[4]

Prove that:

a.

$sec⁡4A−tan⁡4A≡2sec⁡2A−1\sec^4 A - \tan^4 A \equiv 2\sec^2 A - 1$

[2]

b.

Hence solve, for $\leq A \leq 360$ , the equation,

sec^4 A - \tan^4 A = 3

[4]

3.5 Trigonometry (A-level only) Questions