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Differential equation help

10i)

http://www.ocr.org.uk/Images/59552-question-paper-unit-4724-01-core-mathematics-4.pdf


For k I got .07438118316

The answer for k is .07438118377

I can't figure out where I have gone wrong...

I got K = Ln [ 3^(-1/3) * 5^(1/3) ] - 0.2310490602
Original post by IShouldBeRevising_
10i)

http://www.ocr.org.uk/Images/59552-question-paper-unit-4724-01-core-mathematics-4.pdf


For k I got .07438118316

The answer for k is .07438118377

I can't figure out where I have gone wrong...

I got K = Ln [ 3^(-1/3) * 5^(1/3) ] - 0.2310490602


Assuming you used the partial fractions form in (i) to do (ii), you may have made an error integrating or using the initial conditions.

Post working :smile:
Reply 2
Original post by IShouldBeRevising_
10i)

http://www.ocr.org.uk/Images/59552-question-paper-unit-4724-01-core-mathematics-4.pdf


For k I got .07438118316

The answer for k is .07438118377

I can't figure out where I have gone wrong...

I got K = Ln [ 3^(-1/3) * 5^(1/3) ] - 0.2310490602


Where have you got all those horrible decimals from?

The answer is given in an exact form, so keep everything expressed as ln(something) until you get to the very end and then everything drops out nicely!
Original post by davros
Where have you got all those horrible decimals from?

The answer is given in an exact form, so keep everything expressed as ln(something) until you get to the very end and then everything drops out nicely!


Yeah I did again but this time kept everything in exact form and got the correct answer, thanks.

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