Question

hneed your help guys plz solve this math problem

Answer 1

Answer:

Proof below

Step-by-step explanation:

If A = B = 45°

(i)

$\sin45 \cos45 - \cos45 \sin45 \\ \frac{1 \times 1}{2 \times 2} - \frac{1 \times 1}{2 \times 2} \\ \frac{1}{4} - \frac{1}{4} \\ = 0 = \sin0 \\ = \sin(45 - 45) = \sin(a - b)$

Hence proved

(ii)

$\cos45 \cos45 - \sin45 \sin45 \\ \frac{1 \times 1}{2 \times 2} - \frac{1 \times 1}{2 \times 2} \\ \frac{1}{4} - \frac{1}{4} \\ = 0 = \cos90 \\ = \cos(45 + 45) = \cos(a + b)$

Hence proved