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# C2 Trigonometry identities watch

1. I need some help with trigonometry identities as I missed the lessons we had on them and I need to do some homework for it. Could someone please tell me how to do them with a walkthrough please(for just one question should be enough)? And the same for the proof question please. Thanks in advance

Section B: Solve each equation in the range 0° ≤ x ≤ 360°. Give answers correct to 1 decimal place.
13. 3−3cos𝑥=2sin^2𝑥
18. sin 2x = - ½
19. tan (2x+45) = 1.732

23. Prove the following identity:
(d) cos4𝜃−sin4𝜃≡cos2𝜃
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