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

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
3854 answers (Tutor Details)
Differentiating e gives you e again. But there is a chain '-0.3t' to be differentiated.
Eric Nicholas K
Eric Nicholas K
7 months ago
(a) is simply solving an exponential equation for t.

(c) is setting t to a large number so e to the power of -0.3t is a very tiny number.