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Differentiating C3

how to differentiate this 20(1-e^-0.2t) when t=2 to get the answer 4e^-0.2t ?!!
I really tried many times but could not this answer >_<
Any help? Thank you

Reply 1

smartalan73

Original post by yoomi

how to differentiate this 20(1-e^-0.2t) when t=2 to get the answer 4e^-0.2t ?!!
I really tried many times but could not this answer >_<
Any help? Thank you

Expand the brackets and differentiate each term individually (hint: 20 differentiated disappears so all you're actually differentiating is -20e^-0.2t)

Reply 2

yoomi

Original post by smartalan73

Expand the brackets and differentiate each term individually (hint: 20 differentiated disappears so all you're actually differentiating is -20e^-0.2t)

I just did it again and figured it out lol I dunno what I have done wrong before :colondollar:

Thank you anyway :h:

Reply 3

TheFarmerLad

Original post by yoomi

how to differentiate this 20(1-e^-0.2t) when t=2 to get the answer 4e^-0.2t ?!!
I really tried many times but could not this answer >_<
Any help? Thank you

20(1-e^-0.2t) = 20-20e^-0.2t. differentiating with respect to t. use the chain rule. differential of e^t = e^t. so differential of e^-0.2t = e^-0.2t x -0.2 (differential of -0.2t). therefore differential of 20-20e^-0.2t = -20e^-0.2t x -0.2 = 4e^-0.2t. Then sub t=2 into the result.