Erfana Beevee Binte Hassan Shariff's answer to Jung Wook Young's Secondary 4 A Maths Singapore question.

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Erfana Beevee Binte Hassan Shariff
Erfana Beevee Binte Hassan Shariff's answer
275 answers (Tutor Details)
Use laws of natural log to split ln (a/b) into lna -lnb and then differentiate.
Recall gradient of 2 perpendicular lines, when multiplied = -1