Eric's answer to Noel's Junior College 2 H3 Maths Singapore question.
done
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clear
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Use all the limit laws to help you.
Date Posted:
5 years ago
It should be -7x² instead of -7x. And the right hand side expression cannot be divided by x³ throughout as there's no denominator unlike x²/(x - 8). You would be reducing the limit this way.
How you showing me the correct working for analysis??
From your 3rd last step :
(1 + lim ( (x²/x²)/(2/x - 8/x²) )^⅓ ) ( lim(x³ - 7x² - 4) )
= (1 + (1/(2/8 - 8/8²))^⅓ ) (8³ - 7(8)² - 4)
= (1 + (1/⅛)^⅓ ) (512 - 448 - 4)
= (1 + 8^⅓)(60)
= (1 + 2)(60)
= 3 x 60
= 180
(1 + lim ( (x²/x²)/(2/x - 8/x²) )^⅓ ) ( lim(x³ - 7x² - 4) )
= (1 + (1/(2/8 - 8/8²))^⅓ ) (8³ - 7(8)² - 4)
= (1 + (1/⅛)^⅓ ) (512 - 448 - 4)
= (1 + 8^⅓)(60)
= (1 + 2)(60)
= 3 x 60
= 180
J : Do you have alternative solution to this question?
I got 180 as well, can you take a look at my ans and see if I presented correctly?
Congrat Noel! Most important is that your underlying principle must be correct.
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