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.

44<br />

'<br />

Differentiation of Functions [Ch. 2<br />

are called, respectively, the left-hand or right-hand derivative of the function<br />

f(x) at the po<strong>in</strong>t x. For /' (x) to exist, it is necessary and sufficient that<br />

Example 4 F<strong>in</strong>d /'_ (0) and /'+ (0)<br />

Solution. By<br />

/'.(*) = /+(*).<br />

the def<strong>in</strong>ition we have<br />

/'_ (0) = lim L<br />

f^ (0) = lim<br />

A*--t-o Ax<br />

of the function<br />

4. Inf<strong>in</strong>ite derivative. If at some po<strong>in</strong>t we have<br />

lim /(*+**)-/(*)_.<br />

Uoo,<br />

then we say that the cont<strong>in</strong>uous function / (x) has an <strong>in</strong>f<strong>in</strong>ite derivative at x.<br />

In this case, the tangent to the graph of the function y = f(x) is perpendicular<br />

to the x-axis.<br />

Example 5. F<strong>in</strong>d /' (0) of the function<br />

V=V*<br />

Solution. We have<br />

/'0)=llm *~ = ]im -=-=

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

Saved successfully!

Ooh no, something went wrong!