Calculus Help

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  • Windscarredfaith
    (づ ̄ ³ ̄)づ watermelon
    • Mar 2005
    • 2612

    #1

    Calculus Help

    THIS THREAD IS USELESS NOW UNLESS YOU SOMEHOW HAVE THE SAME QUESTIONS AS THESE.
    I thank all the people who attempted and took time to help me out. <33 You guys are the best. ^^

    ---
    M'kay. So my teacher Mr. Furry (his real name, I'm not kidding) just gave my class and I some questions that we didn't even learn. =/ It's due tonight at 11:55 PM EST... so, if you have some time (or if you are extremely bored), please help! I have NO idea how to do these. Lol. Any help is appreciated. (I'm in high school, btw.) Thanks in advance.

    Here are the questions that I don't know how to do:

    1. The area of a square with sides of length s is given by A = s2. Find the rate of change of the area with respect to s when s = 5 meters.
    Answer is in meters^2. And it is not 25.

    2. Consider the following function.
    f(t) = 6t^2 - 4
    (a) Find the average rate of change of the function below over the interval [5, 5.1].
    Answer is not the average of the numbers plugged in...
    (b) Compare this average rate of change with the instantaneous rates of change at the endpoints of the interval.
    Answer will have one at t=5 and another with t=5.1

    3. Use the position function -16t^2 + vot + so for free-falling objects.
    (a) A ball is thrown straight down from the top of a 240 foot building with an inital velocity of -25 feet per second. What is its velocity after 5 seconds?
    Answer is in ft/sec.
    (b) What is its velocity after falling 103 feet?
    Answer is also in ft/sec.

    4. Find k such that the line y = 5x + 6 is tangent to the graph of the function below. y=k*sqrt(x)
    Answer is what k equals.

    5. The tangent line to the graph of y = h(x) at the point (-7, 6) that passes through the point (2, 8). Find the following values.
    (a) h(-7)
    (b) h '(-7)

    6. (Use the position function -4.9t^2 + vot + so for free-falling objects.) To estimate the height of a building, a stone is dropped from the top of the building into a pool of water at ground level. How high is the building if the splash is seen 5.2 seconds after the stone is dropped?

    -- Edit

    Answer for 1 is 10.

    -- Edit #2

    Answer is 60.6, 60, and 61.2 respectfully.

    -- Edit #3

    Disregard #3. I maxed out my submissions for the question. xD
    3a was -185 though.

    -- Edit #4
    Answer is 11. I BSed that one.

    -- Edit #5
    Answer to part 2 is 2/9. Maxed out submissions for part 1, so disregard this question now.
    And... YAY ONLY #6 LEFT!

    -- Edit #6
    Answer is 132.496.
    Last edited by Windscarredfaith; 12-7-2006, 06:49 PM.
  • GuidoHunter
    is against custom titles
    • Oct 2003
    • 7371

    #2
    Re: Calculus Help

    1. dA/ds = 2s. dA/ds|s=5 = 2(5) = 10, though I don't see how it can be in m^2

    2. df/dt = 12t. df/dt|t=5 = 60. df/dt|t=5.1 = 61.2 Average = 60.6

    3. s = -16t^2 + vot + so
    v = -32t + vo
    v|vo=-25, t=5 = -160 - 25 = -180

    (b) s = -16t^2 + vot + so
    137 = -16t^2 - 25t + 240

    EDIT: d'oh about 3

    --Guido

    Last edited by GuidoHunter; 12-7-2006, 06:39 PM.

    Originally posted by Grandiagod
    Originally posted by Grandiagod
    She has an asshole, in other pics you can see a diaper taped to her dead twin's back.
    Sentences I thought I never would have to type.

    Comment

    • Windscarredfaith
      (づ ̄ ³ ̄)づ watermelon
      • Mar 2005
      • 2612

      #3
      Re: Calculus Help

      Lol, yeah... those are the questions I got.. ^^"

      Comment

      • itmorr
        Custom User Title
        • Jun 2006
        • 1498

        #4
        Re: Calculus Help

        On #5, find the y=mx+b for the tangent line. Slope is the difference in y over difference in x. Substitute an x and y pair in to find b. Then with h(x), plug the x value into your new mx+b to find y.




        Originally posted by jwcgator
        (12:31:27 AM) jwcgator2: I got it! I'll write an auto-procrastination program!
        (12:31:33 AM) jwcgator2: meh, i'll make it later

        Comment

        • Doug31
          Falcon Paaaauuuunch!!!!!!
          FFR Simfile Author
          • Jun 2004
          • 6811

          #5
          Re: Calculus Help

          Here's what I got for 5, haven't done the others yet.

          5. tangent line -> y=9/2x +1, so h(7)=9/2(7) +1 = 22.5, and h'(7)=9/2

          Comment

          • Windscarredfaith
            (づ ̄ ³ ̄)づ watermelon
            • Mar 2005
            • 2612

            #6
            Re: Calculus Help

            Tried the answers. Both wrong. =/

            Comment

            • itmorr
              Custom User Title
              • Jun 2006
              • 1498

              #7
              Re: Calculus Help

              The slope on that should be 2/9 not 9/2.
              => h'(x) = 2/9




              Originally posted by jwcgator
              (12:31:27 AM) jwcgator2: I got it! I'll write an auto-procrastination program!
              (12:31:33 AM) jwcgator2: meh, i'll make it later

              Comment

              • talisman
                Resident Penguin
                FFR Simfile Author
                • May 2003
                • 4598

                #8
                Re: Calculus Help

                3a is -205 but I got that doing it in my head so it's probably wrong.

                Comment

                • Windscarredfaith
                  (づ ̄ ³ ̄)づ watermelon
                  • Mar 2005
                  • 2612

                  #9
                  Re: Calculus Help

                  Yeah. That one is right. <-- to what itmorr said

                  And, disregard 3, my submissions are gone.

                  Comment

                  • Doug31
                    Falcon Paaaauuuunch!!!!!!
                    FFR Simfile Author
                    • Jun 2004
                    • 6811

                    #10
                    Re: Calculus Help

                    Okay, here's another, although very confusing of a way of doing it, but I think it's the right answer.
                    6. x=xo +vot +1/2at^2, so x-xo=1/2*4.9*5.2^2=66.248meters

                    Comment

                    • talisman
                      Resident Penguin
                      FFR Simfile Author
                      • May 2003
                      • 4598

                      #11
                      Re: Calculus Help

                      well 6 is easy just move the h sub zero over to the left side and plug in the 5.2 and I think that will do it.

                      Comment

                      • Windscarredfaith
                        (づ ̄ ³ ̄)づ watermelon
                        • Mar 2005
                        • 2612

                        #12
                        Re: Calculus Help

                        Nope.... Lol. Sorry. ^^"

                        Comment

                        • Doug31
                          Falcon Paaaauuuunch!!!!!!
                          FFR Simfile Author
                          • Jun 2004
                          • 6811

                          #13
                          Re: Calculus Help

                          Tried 5 again.

                          5. tangent line -> y=2/9x +68/9, so h(7)=2/9(7) +68/9 = 89/9, and h'(7)=2/9
                          Even though you're done with that now.

                          Edit, okay, so my answer for 6 was wrong, because the -4.9 already had the 1/2 in it, so I now think it's 132.496meters.

                          Comment

                          • Windscarredfaith
                            (づ ̄ ³ ̄)づ watermelon
                            • Mar 2005
                            • 2612

                            #14
                            Re: Calculus Help

                            Lol. Thanks for that. I got 1/2 credit. xD

                            -- Edit

                            YAY! #6 is right. ^^
                            Last edited by Windscarredfaith; 12-7-2006, 06:48 PM.

                            Comment

                            • itmorr
                              Custom User Title
                              • Jun 2006
                              • 1498

                              #15
                              Re: Calculus Help

                              Does this work on the one you BS'd as 11?
                              y=k*sqrt(x) curve
                              y = 5x + 6 tangent to curve
                              5x + 6 = k*sqrt(x)
                              5x + 6 over sqrt(x) = k




                              Originally posted by jwcgator
                              (12:31:27 AM) jwcgator2: I got it! I'll write an auto-procrastination program!
                              (12:31:33 AM) jwcgator2: meh, i'll make it later

                              Comment

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