# Trig Questions (1 Viewer)

#### bujolover

##### Active Member
Hi guys,
Could you please confirm for me that the given answers to the following questions are incorrect, based on their given working? I strongly believe that they're wrong, but I want to be certain. c:

Q1. - Is the correct answer cotx?

Q2. If sinx = 2/√7 and cosx<0, find the exact value of tanx.

- Given working. Shouldn't it be -(2√3)/3?

Q3. From the top of a lighthouse 70m above sea level, the angles of depression of two buoys due north of the lighthouse are 60 deg. and 25 deg. respectively. Find the distance between the two buoys. (Answer in 2 dec. pl.)

- Shouldn't it be 109.70m (2 dec. pl.)?

Q4. Highlighted questions =>

Given working: - Shouldn't it be for (iii), BQ = htan79°, and for (iv), h = 108m (nearest m)?

P.S. Please don't feel like you need to answer all the questions at once. Any help is help!

#### InteGrand

##### Well-Known Member
Hi guys,
Could you please confirm for me that the given answers to the following questions are incorrect, based on their given working? I strongly believe that they're wrong, but I want to be certain. c:

Q1. View attachment 33900 - Is the correct answer cotx?

Q2. If sinx = 2/√7 and cosx<0, find the exact value of tanx.

View attachment 33901 - Given working. Shouldn't it be -(2√3)/3?

Q3. From the top of a lighthouse 70m above sea level, the angles of depression of two buoys due north of the lighthouse are 60 deg. and 25 deg. respectively. Find the distance between the two buoys. (Answer in 2 dec. pl.)

View attachment 33897 - Shouldn't it be 109.70m (2 dec. pl.)?

Q4. Highlighted questions => View attachment 33898

Given working: View attachment 33899 - Shouldn't it be for (iii), BQ = htan79°, and for (iv), h = 108m (nearest m)?

P.S. Please don't feel like you need to answer all the questions at once. Any help is help!
Q1 answer is cot(x). The solutions wrote tan(x) in line 3, but they had cos(x)/sin(x) before that, which is cot(x), not tan(x).

#### bujolover

##### Active Member
Q1 answer is cot(x). The solutions wrote tan(x) in line 3, but they had cos(x)/sin(x) before that, which is cot(x), not tan(x).
Thanks. That's what I thought.

#### jathu123

##### Active Member
Hi guys,
Could you please confirm for me that the given answers to the following questions are incorrect, based on their given working? I strongly believe that they're wrong, but I want to be certain. c:

Q1. View attachment 33900 - Is the correct answer cotx?

Q2. If sinx = 2/√7 and cosx<0, find the exact value of tanx.

View attachment 33901 - Given working. Shouldn't it be -(2√3)/3?

Q3. From the top of a lighthouse 70m above sea level, the angles of depression of two buoys due north of the lighthouse are 60 deg. and 25 deg. respectively. Find the distance between the two buoys. (Answer in 2 dec. pl.)

View attachment 33897 - Shouldn't it be 109.70m (2 dec. pl.)?

Q4. Highlighted questions => View attachment 33898

Given working: View attachment 33899 - Shouldn't it be for (iii), BQ = htan79°, and for (iv), h = 108m (nearest m)?

P.S. Please don't feel like you need to answer all the questions at once. Any help is help!
2. Yes, it should be -(2√3)/3
3. Yes, it should be 109.70m
4. You are correct for both parts, they are indeed htan79 and 108m

#### bujolover

##### Active Member
2. Yes, it should be -(2√3)/3
3. Yes, it should be 109.70m
4. You are correct for both parts, they are indeed htan79 and 108m
Thanks a million.