hi:) for 5(b) , I got 157.7 & 22.3 but in the answer key, the only correct answer is 157.7. I thought there should be 2 poss

Question

Katen [24]

4 years ago

6

hi:) for 5(b) , I got 157.7 & 22.3 but in the answer key, the only correct answer is 157.7. I thought there should be 2 poss

ible values?

Mathematics

2 answers:

n200080 [17] · Answer 1 · 2021-11-11T09:43:16+03:00

n200080 [17]4 years ago

8 0

Answer:

Θ = 157.7°

Step-by-step explanation:

Given

cosΘ = - 0.925

Since cosΘ < 0 then Θ is in the second or third quadrant.

Since 0° ≤ Θ ≤ 180° then Θ is in the second quadrant. thus

Θ = $cos^{-1}$ (- 0.925) = 157.7° ← angle in second quadrant

inna [77] · Answer 2 · 2021-11-11T11:24:42+03:00

Answer:

There should be only 1 value (157.7°) since we reject the second value as θ lies in quadrant 1 and 2. Note that the 2nd value should have been 202.3°, which is greater than 180°.

Cosine of an angle negative in the 2nd and 3rd quadrant.

Step-by-step explanation:

Please see attached picture.