3.4 Trigonometry (A-level only)

Prove that:

a.

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

[3]

b.

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

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

[4]

Prove that:

a.

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

[3]

b.

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

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

[4]

3.4 Trigonometry (A-level only) Questions