>
    variable <span class="string">x_c(2)</span>
    maximize ( r )
    a1'*x_c + r*norm(a1,2) &lt;= b(1);
    a2'*x_c + r*norm(a2,2) &lt;= b(2);
    a3'*x_c + r*norm(a3,2) &lt;= b(3);
    a4'*x_c + r*norm(a4,2) &lt;= b(4);
cvx_end

<span class="comment">% Generate the figure</span>
x = linspace(-2,2);
theta = 0:pi/100:2*pi;
plot( x, -x*a1(1)./a1(2) + b(1)./a1(2),<span class="string">'b-'</span>);
hold <span class="string">on</span>
plot( x, -x*a2(1)./a2(2) + b(2)./a2(2),<span class="string">'b-'</span>);
