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secondary 4 | A Maths
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kim Yeon Jae
Kim Yeon Jae

secondary 4 chevron_right A Maths chevron_right Singapore

Please help me with this qn thanku :)

Date Posted: 4 years ago
Views: 215
J
J
4 years ago
2 + lg√(1 + x) + 3lg√(1 - x) = lg√(1 - x²)

2lg10 + lg√(1 + x) + lg√(1 - x) + 2lg√(1 - x)
= lg√((1 + x)(1 - x))


lg10² + lg√(1 + x) + lg√(1 - x) + lg(√(1 - x))²
= lg√(1 + x) + lg√(1 - x)


lg100 + lg(1 - x) = 0

lg(100(1 - x)) = 0

100 - 100x = 1

99 = 100x

x = 99/100 = 0.99

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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
1st
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kim Yeon Jae
Kim Yeon Jae
4 years ago
Thanku so much!
J
J
4 years ago
Alternative with a different approach from these 2 provided in the main comments section, may help in your understanding
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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
Alternative