Eric Nicholas K's answer to sonia's Secondary 4 A Maths Singapore question.

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Eric Nicholas K
Eric Nicholas K's answer
1964 answers (Tutor Details)
The chain rule is again to be used here. The first chain is the large bracket attached to the ln, because otherwise you would just be differentiating ln x, but instead it’s the ln of something else.

We can treat the derivative of the term in the large brackets as a separate bracket. There will be a chain rule element involved in differentiating the (x2 + 1)^0.5; the chain this time is (x^2 + 1), because we are otherwise simply differentiating x^0.5 easily.