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. 4] Change of Variable <strong>in</strong> a Def<strong>in</strong>ite Integral 147<br />

then<br />

Example<br />

1. F<strong>in</strong>d<br />

Solution. We put<br />

x* V~a*x*dx (a > 0).<br />

as<strong>in</strong> t\<br />

Then ? = arc s<strong>in</strong> and, consequently, we can take a = arcs<strong>in</strong>O = 0,<br />

P= arc s<strong>in</strong> l = y .<br />

IL<br />

a 2<br />

Therefore, we shall have<br />

C x 2 VV x 2<br />

dx=\ a2 s<strong>in</strong> 2 1 J/~a 2<br />

jl JL<br />

2 Z<br />

dt.<br />

a 2 s<strong>in</strong> 2 1 a cos t dt<br />

= a 4 f s<strong>in</strong> 2 / cos 2 / d/ = -^- f s<strong>in</strong> 2 2/ d/ = -^- C (1<br />

1576. Can the substitution A: = COS/ be made <strong>in</strong> the <strong>in</strong>tegral<br />

Transform the follow<strong>in</strong>g def<strong>in</strong>ite <strong>in</strong>tegrals by means of the<br />

<strong>in</strong>dicated substitutions:<br />

1577.<br />

1578<br />

8<br />

i<br />

. ly=,<br />

IL<br />

t<br />

Jtfl<br />

. f(x)dx, x = arc tan/.<br />

1581. For the <strong>in</strong>tegral<br />

b

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

Saved successfully!

Ooh no, something went wrong!