12.07.2015 Views

Advanced Calculus fi..

Advanced Calculus fi..

Advanced Calculus fi..

SHOW MORE
SHOW LESS
  • No tags were found...

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

[Hint: Use induction. For n = 0 the formula becomes the known ruleChapter 6 In<strong>fi</strong>nite Series 437Suppose the formula is true with n replaced by m and prove it is true for m + 1; for thisstep, integrate the remainder term by parts taking u = f(m+')(t), dv = (x - t)m dtlm!.]5. Evaluate to threc decimal places:,0.5 dxa) jd ePxzdx"J,6. Let f (x) = e-'1"' for x # 0 and let f (0) = 0.a) Prove that f (x) is continuous for all x.b) Prove that f '(x) is continuous for x # 0 and thatlim f '(x) = f '(0) = 0,x-toso that f '(x) is continuous for all x. . .. .c) Prove that f (")(x) is continuous for all x and f (")(O) = 0.d) Graph the function f (x).7. Use the remainder formula to estimate the error in the following computations:a) e = 1 + 1 + + + & + 4 [assume that e < 3 is known)1 1c ) l o g ; = ; - ~ + ~8. Let f (x) satisfy the conditions stated in Theorem 41. Let f '(a) = f "(a) = ... =f (")(a) = 0, but f ("+')(a) # 0. Show that f (x) has a maximum, minimum, or horizontalinflection point at x = a according to whether the function f("+')(a)(x - a)"+' has amaximum, minimum, or inflection point for x = a. (This gives another proof of the rulededuced in Section 2.19.)9. (Derivatives and differences) In numerical analysis, one uses approximations for derivatives.For the <strong>fi</strong>rst derivative of f (x) at x, one chooses a small positive h and usesFor the second derivative, one usesWith the aid of Taylor's formula with remainder (assuming suf<strong>fi</strong>cient differentiability),establish the following:a) gl(x,h)- f'(x)haslimitOash + Oand hasa<strong>fi</strong>nitelimitash-r 0.b) g2(x, h) - f '(x) has limit 0 as h -+ 0 and 8- has a <strong>fi</strong>nite limit as h -r 0.C) g3(x. h) - f "(x) has limit 0 as h -r 0 and has a <strong>fi</strong>nite limit as h -r 0.Remark We describe these results by saying that the error in approximating fl(x) bygl(x, h) or ftl(x) by g3(x, h) is of the order h, while the error in approximating f1(x)by gz(x, h) is of the order h2. (The higher the power of h, the better the approximation forsmall h.)0

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!