Ask Singapore Homework?
Upload a photo of a Singapore homework and someone will email you the solution for free.
Question
secondary 4 | A Maths
2 Answers Below
Anyone can contribute an answer, even non-tutors.
Differentiation
Date Posted: 4 years ago
Views: 443
Hang on, sending you this later
Yes please Thankyou, answer is 24.6
Hang on, the given answer looks off, I obtained 44+, let me check my workings
Here, we must introduce a variable x somewhere along AB to solve this question. Without this, solving for the distance AP may be challenging.
You can use AP = x m and PB = (90 - x) m to solve this question, but I avoided this as the Pythagoras Theorem will be more complicated. Nevertheless, we should get a similar solution.
I have confirmed with Desmos and in this other case AP = 44.644 m.
You were once a regular forum responder here as well, and your workings were often much more detailed than mine. So if you feel my workings are not detailed enough, let me know,
You can use AP = x m and PB = (90 - x) m to solve this question, but I avoided this as the Pythagoras Theorem will be more complicated. Nevertheless, we should get a similar solution.
I have confirmed with Desmos and in this other case AP = 44.644 m.
You were once a regular forum responder here as well, and your workings were often much more detailed than mine. So if you feel my workings are not detailed enough, let me know,
No your workings are very detailed. I am actually helping a friend with this question haha. I’m trying to get back on the forum to help others as I stopped once Olevels ended but I’ve gotten rusty :(
See 2 Answers
done
{{ upvoteCount }} Upvotes
clear
{{ downvoteCount * -1 }} Downvotes
Something like this looks good. I obtained 44.6 m for my workings.
Here, I made an initial mistake of summing up the distances, in which case I would obtain the shortest distance (which in fact is AQ!), but this does not lead to the shortest time possible.
What answer did you manage to get for this question?
Here, I made an initial mistake of summing up the distances, in which case I would obtain the shortest distance (which in fact is AQ!), but this does not lead to the shortest time possible.
What answer did you manage to get for this question?
Date Posted:
4 years ago
done
{{ upvoteCount }} Upvotes
clear
{{ downvoteCount * -1 }} Downvotes
Here is the relevant Desmos plot for the graph.
If PB = x m, then AP = (90 - x) m and PQ = ./ (x^2 + 1600) m.
Since he can run from A to P at a speed of 8 m/s, time taken to travel from A to P
= Distance / Time
= (90 - x) / 8 s
Since he can run from P to Q at a speed of 6 m/s, time taken to travel from P to Q
= Distance / Time
= [./ (x^2 + 1600) ] / 8 s
Their sum is the total time taken. In any case the minimum point of the graph is located at x = 45.356. It follows that the distance AP = 90 - x = 44.644 m.
Something is not exactly right with the given solution of x = 24.6 m.
If PB = x m, then AP = (90 - x) m and PQ = ./ (x^2 + 1600) m.
Since he can run from A to P at a speed of 8 m/s, time taken to travel from A to P
= Distance / Time
= (90 - x) / 8 s
Since he can run from P to Q at a speed of 6 m/s, time taken to travel from P to Q
= Distance / Time
= [./ (x^2 + 1600) ] / 8 s
Their sum is the total time taken. In any case the minimum point of the graph is located at x = 45.356. It follows that the distance AP = 90 - x = 44.644 m.
Something is not exactly right with the given solution of x = 24.6 m.
Date Posted:
4 years ago
360 Tutoring Program