Question

12. If A = 45°, verify that
(ii) cos 2A = 2 cos’A-1=1-2sin’A​

Answer 1

Answer:

Here's your answer

Step-by-step explanation:

$\huge \mathfrak \purple{given}$

A = 45°

$\huge \mathfrak \pink{verify}$

cos 2A = (2 cos² A - 1) = (1 - 2 sin² A)

$\huge \mathfrak \blue{answer}$

cos 2A = cos(2×45°)

= cos = 90°

= 0

2 cos² A-1 = 2 cos² 45°-1

= 2 (1/√2)² -

= 2 × 1 /2 - 1

= 1 - 1

= 0

1 - 2 sin² A = 1 - 2 sin² 45°

= 1 - 2 (1 / √2)²

= 1 - 2 × 1/2

= 1 - 1

= 0

$\huge \mathfrak \red{hence proved}$