Eric Nicholas K's answer to Jessica's Junior College 1 H1 Maths Singapore question.

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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
1st
Chain rule applies as usual. We would be differentiating sin x otherwise, but instead, we are differentiating sin 4x, so we have to differentiate the chain '4x' as well. Similar argument applies for cos 0.5x.

Remember that differentiating sin x gives cos x and differentiating cos x gives -sin x.
Jessica
Jessica
5 years ago
Thank you so much! I get it now :)