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Using left endpts help with squr(3i/16) how to get the i out

  1. Jan 25, 2009 #1
    1. The problem statement, all variables and given/known data
    i am have to approximate the area under the curve using left endpoints.

    2. Relevant equations
    y= squr(x+2) on [1,4], n =16

    3. The attempt at a solution
    i have the change in x to be 3/16 using (b-a)/n i also found my xsubi to be (1+3i/16) using xsubi = xsubo + i(chang in x). then i got (3/16) E (squr(1+(3i/16)+ 2)) i am stuck on how to get the i out to then apply the formula n(n+1)/2 or n(n+1)(2n+1)/6.

    Thank you ahead of time.

    another question similar problem but i get stuck after i dont know how to take the i out of cos(pi(i)/100) i tried multiplying by sec but i still dont get the right answer. do i multiply by sec? to get the i out of cos(pi(i)/100)?
    Last edited: Jan 25, 2009
  2. jcsd
  3. Jan 26, 2009 #2

    Gib Z

    User Avatar
    Homework Helper

    You can't apply those summations to this one, the first one applies to linear functions and the second to quadratics, but for this one all they want is to use left rectangles.

    You know the x values you have to set up the rectangles at, and the width (3/16). Now all you have to do is multiply each by f(x) at the point you set up the rectangle at, them sum them all up. Simple, but tedious process.
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