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.

Answer This Question
Kathy
Kathy

secondary 4 chevron_right A Maths chevron_right Singapore

Thank you

Date Posted: 5 years ago
Views: 382

See 2 Answers

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
1st
Part a, part b
Kathy
Kathy
5 years ago
When can I use the U formula for logarithm?
Eric Nicholas K
Eric Nicholas K
5 years ago
You will notice that two terms are exactly the same. I let u = log 5 x, for example, to simplify matters because it is easier to see the expressions in that way. It’s not a must to let u be something though.
Kathy
Kathy
5 years ago
I send u a qns, can you use U formula for Me. Thanks
Eric Nicholas K
Eric Nicholas K
5 years ago
For example, if (5^x)^2 - 2 (5^x) + 1 = 0, letting u = 5^x (you can use other letters also) transforms the equation into u^2 - 2u + 1 = 0 which you immediately recognise to be a quadratic equation.

We then solve the quadratic equation followed by solving for x.
Eric Nicholas K
Eric Nicholas K
5 years ago
Done up - in that expression we only have x and y after conversion so there is no need to replace x or y by u.
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
Part c, part d