29.01.2013 Views

Problems in Mathematical Analysis.pdf - pwp.net.ipl.pt

Problems in Mathematical Analysis.pdf - pwp.net.ipl.pt

Problems in Mathematical Analysis.pdf - pwp.net.ipl.pt

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Sec. 5]_Derivatives of Higher Orders_67<br />

Generally, the ith derivative of a function y f(x) is the derivative of<br />

a derivative of order (n 1). For the nth derivative we use the notation<br />

Example<br />

y (v t or ~^, or f (n) (x).<br />

t. F<strong>in</strong>d the second derivative of the function<br />

Solution. /.JZL; /<br />

y = \n(\ x).<br />

2. Leibniz rule. If the functions u = q>(x) and v=ty(x) have derivatives<br />

up to the nth order <strong>in</strong>clusive, then to evaluate the nth derivative of a product<br />

of these functions we can use the Leibniz rule (or formula):<br />

(uv) (0,<br />

I i^ = *(0,<br />

then the derivatives y'x = -r f/^jc == ^2<br />

by<br />

the formulas<br />

x t<br />

For a second derivative we have the formula<br />

and<br />

Example 2. F^nd w<br />

/ ,<br />

Solution. We have<br />

.<br />

*<br />

If<br />

if<br />

x t<br />

_ & . cos f &<br />

- "~~ "~~~<br />

. . / . LUl I<br />

(a cos*),<br />

(acosO<br />

asm* a<br />

can successively be calculated<br />

-asln< osln

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

Saved successfully!

Ooh no, something went wrong!