Integrais duplas em coordenadas polares

Seja $R$R a região dentro das curvas polares $r = \cos(\theta)$r, equals, cosine, left parenthesis, theta, right parenthesis and $r = -\operatorname{sen}(\theta)$r, equals, minus, s, e, n, left parenthesis, theta, right parenthesis, sendo $-\dfrac{\pi}{2} < \theta < -\dfrac{\pi}{4}$minus, start fraction, pi, divided by, 2, end fraction, is less than, theta, is less than, minus, start fraction, pi, divided by, 4, end fraction.

Seja $f(x, y) = x^2 + y^2$f, left parenthesis, x, comma, y, right parenthesis, equals, x, squared, plus, y, squared.