Recent content by MMM

  1. M

    Integration by trigonometric change of variable

    Homework Statement I'm trying to solve ##\int\sqrt{a^2 - x^2}## by using the substitution ##x = asin\theta## Homework Equations ##x = asin\theta The Attempt at a Solution ##y = \int\sqrt{a^2 - a^2cos^2\theta}## ##y = a\int\cos\theta## ##y = a^2\int\cos(\theta)^2## ##y = (a^2)/2 *...
  2. M

    How do I know what to substitute(u-substitution)

    Thanks for the help. I understand it now!
  3. M

    How do I know what to substitute(u-substitution)

    Homework Statement Hello, I'm having trouble determining what I make u equal with most integrals that revolve around the inverse trig functions. I knew what to let u equal in this problem ##x/\sqrt{1-x^4}## I let it equal ##x^2## and correctly solved the problem. The problems I'm having...
  4. M

    Understanding the Trapezoidal Rule for Approximating Definite Integrals

    Homework Statement I'm curious about how the trapezoidal rule is derived for approximating definite integrals. Homework Equations According to my calculus book the equation is $$h[(1/2)y_{0} + y_{1} + y_{2} + ... +y_{n-1} + (1/2)y_{n}]$$ The Attempt at a Solution I'm curious as to why the...
  5. M

    Finding area by using a summation

    I split the sum into two different parts. \lim_{n\rightarrow +\infty}\sum_{i=1}^n 8/n and I got that limit to be 8. Now the second sum is \lim_{n\rightarrow +\infty}\sum_{i=1}^n 32i/n^2 and I can't figure out what that limit is. How do I rewrite it as a function of n? Since the final answer...
  6. M

    Finding area by using a summation

    f(xi) = 2(1 + 4i/n) I edited the first post with that information. I just don't understand why the answer to the problem is 24 and not 8, I have no idea what I did wrong when evaluating the limits. Isn't this \lim_{n\rightarrow +\infty}(4/n) * \sum_{i=1}^\infty\frac{8i}{n} 0? I just don't...
  7. M

    Finding area by using a summation

    Hello everyone, I've been working on an area summation problem in my book for quite a bit and I can't solve it. Find the area under the straight line y=2x between x = 1 and x = 5 The book shows the answer as 24 and Maple does as well, but I'm not getting 24, I'm getting 8. Area summation formula...
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