This is for discussing assignments from WEEK 4 & 5 (this week will count as 1.5 weeks for your discussion board bonus), including homework, turn-in, and in-class work or lessons, or anything else related to the class from this week. Please be sure to include your name at the end of your post for credit. When answering a question, DO NOT GIVE SOLUTIONS! Provide hints or explain a method that you used, but do not give the final result. As always, RESPECT IS A MUST! Anyone abusing this forum will be banned from future use (meaning, no extra credit!!!).
Wednesday, September 24, 2014
Week 4.5-5 Discussion (9/24 - 10/3)
This is for discussing assignments from WEEK 4 & 5 (this week will count as 1.5 weeks for your discussion board bonus), including homework, turn-in, and in-class work or lessons, or anything else related to the class from this week. Please be sure to include your name at the end of your post for credit. When answering a question, DO NOT GIVE SOLUTIONS! Provide hints or explain a method that you used, but do not give the final result. As always, RESPECT IS A MUST! Anyone abusing this forum will be banned from future use (meaning, no extra credit!!!).
Subscribe to:
Post Comments (Atom)
In class, we frequently used the notation "dy/dx". Mr. Wilcon said that it signifies "the derivative of y with respect to x", but what exactly does that mean/signify? I still can't wrap my head around this concept
ReplyDelete-Rafey Rehman
I'm not entirely sure about this either, but here's what I think. Derivative is slope, so it's a rate of change. When we take the derivative of y with respect to x, we're finding the change in y over the change in x, or how quickly y changes as x changes. For example, taking the derivative of a position function with respect to time tells us how quickly position changes over a certain time interval, which is velocity.
Delete-Safia Sayed
Safia is right on. See the handout from section 2.4 that has the various verbiage of what a derivative is. We had a lengthy discussion that day, and every day since we have referred to the derivative function in each of those various ways. We can even take the derivative of a function with respect to y, so dx/dy. what would this represent?
DeleteOn the turn in for question number 1b it asks for what time the particle is farthest to the right. Does this mean there is only one time value because I got multiple time values?
ReplyDeleteThanks!
Laura G
There will be multiple values in your solution.
ReplyDeleteFor 2a in the turn in, should the variable "t" for time be in the answer? If not do we have to substitute it out for something?
ReplyDeleteSarah Fried
You can leave t in your answer.
Delete-Eva A-L
yup, I asked Mr. Wilson in class today. The answer is expressed in terms of t!
DeleteAlso, for 1c is there only one answer?
ReplyDeleteSarah Fried
Since there are multiple answers for 1b, it would make sense for there to be multiple answers for 1c as well.
Delete-Safia Sayed
Actually I read the question wrong. You were right--only one answer for 1c.
Delete-Safia
Is it wrong to have a negative speed if the object is moving towards the left?
ReplyDeleteThanks,
Rachel Hersch
Technically, speed is the absolute value of velocity, so it should not be negative. The answer key, however, has a negative value. Let's assume they asked for velocity.
DeleteWhen solving the related rates word problems, it is a lot like solving physics problems with vectors. In physics, when an object moves to the left, its velocity is negative. For the speed, you take the absolute value of the velocity. However, I think most of the related rates problems are asking for velocity, not speed.
ReplyDeleteAngela Satullo
I'm having some trouble with 9b on the related rates worksheet. I took the derivative with respect to time of the equation A= (2r)^2 - (pi)(r^2) and found r when the area of the circle is 25(pi). Anyone have any idea what I should be doing differently?
ReplyDeleteThanks,
Safia Sayed
You also need dr/dt, which can be found by relating circumference to r and the given rate of change of the circumference.
DeleteShould we have pi included in our answer or can we write the answer as a decimal?
ReplyDelete-Laura G
I think Mr. Wilson said that either answer is acceptable as long as you use the approx. symbol for rounded answers. And know that answers with pi are more exact.
Delete-Julia Trombley
Can someone please explain to me why the answer to number 8 on the related rates worksheet #1 is negative?
ReplyDeleteThanks!
Katie Weitzel
It's not negative--the solution on Mr. Wilson's website is positive. The negative before was probably a typo.
ReplyDelete-Safia Sayed
We found a few typos this AM during X Block. Thanks to those who stopped in! What is up now should be 100% correct.
DeleteFor #3 in the related rates ws #1, is 400km/h dz/dt?
ReplyDeleteSarah Fried
Yes it is.
Delete-Safia Sayed
For number 1 on the turn in should there be 13 points? If so should we use them all?
ReplyDeleteThanks,
Rachel Hersch
Thats what i got, and yes they are all answers.
Delete-Eva Antebi-Lerman
When writing the answer to a related rates question, should we always include the number that we took the related rate at? For example: dh/dt at(line symbol) h=3
ReplyDeleteThanks,
Allison Honet
If you are evaluating the rate at a specific value, then yes, you should use proper notation.
DeleteHow much work do we need to show for a calculator problem?
ReplyDeleteAmanda Bachand
On the sheet Mr. Wilson gave us it says that for numerical integration, solving equations numerically, numerical differentiation, and plotting graphs in arbitrary windows, you have to write the setup, and the result. You have to use calculus to solve anything that isn't one of those four categories.
DeleteHope this helped!
Kai Selwa
So it was said earlier in the blog that 1c on the turn-in only has one answer. Can someone please explain why that is the case?
ReplyDeleteThanks,
Julia Berthel
If you did what I did, you you read the question as when is the particle moving farthest to the left. The question actually asks for when the particle moves fastest to the left, so you should look at the graph for velocity, not position. There's only one minimum on the velocity time graph.
Delete-Safia Sayed
Are we using the fastest value or the fast values?
DeleteThanks,
Rachel Hersch
What are some real world applications of taking the inverse of a derivative? I see many uses for derivatives, but I can't think of any situation in which the inverse of a derivative can be used...
ReplyDelete-Rafey Rehman
Here's what I found for a real world application: http://www.ugrad.math.ubc.ca/coursedoc/math100/notes/zoo/fish.html
DeleteHope it helps!
-Abby Siegal
Do we need to graph 30c (p.133) on our paper or can we just look at the graphs on the graphing calculator?
ReplyDeleteThanks,
Allison Honet
I ended up just graphing mine on paper. I graphed it on the calculator first and then used the data table to plot points to draw an accurate graph.
Delete-Jenna Weed
For 3a, should we assume that the cone is full before it began draining? Or should we assume that the volume in the cone is equal to the volume in the cylinder?
ReplyDelete- Daniel Honet
This comment has been removed by the author.
ReplyDeleteDo we have to use related rates in part 3a or are we just writing a simplified equation for the volume of the cylinder? I don't really understand the question.
ReplyDeleteNo, I don think you have to use related rates. You just rewrite the equation so that the only variables left are h and V. Then, rearrange the equation so that it is in terms of h
Delete-Rafey Rehman
Great participation this week (and a half). Turn In #4 has now been collected, so this board will be considered "closed". Any further Q&A will not be counted for EC on this board (or for Turn in 4). Please use the new board for week 6 now. Enjoy your weekend!
ReplyDelete