12.05.2013 Views

f(x) - Campus Rio Pomba

f(x) - Campus Rio Pomba

f(x) - Campus Rio Pomba

SHOW MORE
SHOW LESS

Create successful ePaper yourself

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

Aplicando a integração por partes, vem<br />

e21` sen x dx e2r (- cos x) - f (- cos x) 2e2x dx<br />

—e2x COS X 1- 2 e2x cos x dx.<br />

Introdução à integração 353<br />

Resolvendo .1 e2x cos x dx por partes, fazendo u = e2x e dv = cos x dx,<br />

encontramos<br />

S e2x<br />

sen x dx = -e2x cos x + 2 [e2x sen x - f sen x • 2 elt. dx]<br />

= -e2x cos x + 2 e2x sen x - 4 f ea' sen x dz. (2)<br />

Observamos que a integral do 2 membro é exatamente a integral que quere-<br />

mos calcular. Somando 4 f e2x sen x dx a ambos os lados de (2) , obtemos<br />

5 .1 e2x sen x dx = -e2x cos x + 2 e2x sen x.<br />

Logo,<br />

e2x sen x dx = 5 (2 e2x sen x - e2x cos x) + c .<br />

(v) Calcular f sena x dx.<br />

Neste caso, fazemos<br />

u = sen2 x du = 2 sen x cos x dx<br />

dv = sen x dx v = f sen x dx = - cos x.<br />

.r,<br />

, C' s<br />

ttik -<br />

V --

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

Saved successfully!

Ooh no, something went wrong!