% Example 12-3: Maximum viewing angle

% Do an initial plot
fplot('((x^2+5^2)+(x^2+41^2)-36^2)/(2*sqrt(x^2+5^2)*sqrt(x^2+41^2))', [0 25])
xlabel('x'); ylabel('cos/(\theta)');
pause

% Find the minimum
[x anglecos] = fminbnd('((x^2+5^2)+(x^2+41^2)-36^2)/(2*sqrt(x^2+5^2)*sqrt(x^2+41^2))', 10, 20)
angle = anglecos*180/pi