4. If 2 Cos A-1 = 0, then the value acute value A is

Question

asked Sep 18, 2022 9.3k views

2 Answers

Laurens Rietveld · Answer 1 · 2022-09-22T13:17:37+0000

Answer:

$A=60^(\circ)$

Explanation:

Given
$2\cos A-1=0$ ,

Add 1 to both sides:

$2\cos A=1$

Divide both sides by 2:

$\cos A=(1)/(2)$

Take the inverse cosine of each side (note that the question stipulates that A is acute):

$\arccos(\cos A)=\arccos((1)/(2))$

$A=\arccos((1)/(2)), A\in (0^(\circ), 90^(\circ)),\\A=\boxed{60^(\circ)}$