Ask Singapore Homework?

Upload a photo of a Singapore homework and someone will email you the solution for free.



Question

secondary 4 | E Maths
2 Answers Below

Anyone can contribute an answer, even non-tutors.

Answer This Question
Candice lim
Candice Lim

secondary 4 chevron_right E Maths chevron_right Singapore

Good afternoon Mr Eric, I am stuck at part (b) and (c).
Pls help! Many thanks in advance.

Date Posted: 3 years ago
Views: 553
Eric Nicholas K
Eric Nicholas K
3 years ago
Good evening Candice! I will look at this when I return since I had class the entire day
Candice lim
Candice Lim
3 years ago
Sure, thanks lot Mr Eric. So sorry to trouble you. Do help me on part c of this question when you have time. Take care.

See 2 Answers

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Woon Kiat
Woon Kiat's answer
322 answers (Tutor Details)
1st
Hi, I hope this helps.
Candice lim
Candice Lim
3 years ago
Thanks Mr Woon Kiat. Yes, part b solution is good and I understand :)

But the model answer for part c is 1/sqrt2 q. Could you help to review it again and advise? Many thanks !
Eric Nicholas K
Eric Nicholas K
3 years ago
Part c has a slight misspelling.
Woon Kiat
Woon Kiat
3 years ago
Yup. I think I made a mistake.
Since the vectors are parallel, their ratio would be
|BD| / |AE| = sqrt2 / 2
BD = (sqrt2 / 2) * AE
BD = (sqrt2 / 2) q
I believe Mr Eric gave a good explanation in his answer.
Candice lim
Candice Lim
3 years ago
Thank you for coming back to me Mr Woon Kiat. Really appreciated. I hope you have a good day ahead :)
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
Good morning Candice! For part b we need to find some relevant lengths and cosine rule to solve the question. As it turns out, the included angle happens to be 90 degrees so the “-2ab cos C” term for the cosine rule becomes 0, reducing the formula to the Pythagoras’ Theorem.

For part c, we can simply say that because BD is parallel to AE and the length of BD is (sqrt 2) / 2 times the length of AE, the vector for BD is also (sqrt 2) / 2 times of the vector for AE.
Eric Nicholas K
Eric Nicholas K
3 years ago
Candice, sqrt 2 divided by 2 is equivalent to 1 divided by sqrt 2. This is because 2 can be expressed as sqrt 2 times sqrt 2, such that sqrt 2 divided by (sqrt 2 times sqrt 2) becomes 1 divided by sqrt 2.
Candice lim
Candice Lim
3 years ago
Good morning Mr Eric! Noted your advice with many thanks:)

And thank you so much for your time and effort in providing me with the full solution for the whole question. I really really appreciate what you have done for me thus far and I have to say without your help and advice, I probably wouldn't have come this far. Your commitment and expertise have motivated me to work harder for Mathematics which used to be not my best subjects in school.

You are the BEST teacher that I have ever come across :D

Once again thank you very much and I hope you have a great day ahead, pls take care.