ABC is an isosceles right-angled triangle. Assuming AB = BC = x, find the value of each of the following trigonometric ratios :

(i) sin 45°

(ii) cos 45°

(iii) tan 45°

Prove that :

4 (sin⁴ 30° + cos⁴ 60°) - 3 (cos² 45° - sin² 90°) = 2

If sin x = cos x and x is acute, state the value of x.