MATLAB: How can i find the intersection point between the two curves and the minimum point to the other curve

Question

k1=10^-4;k2=2*10^5
k2 = 200000
d=0.08;
a=50*10^-6:1*10^-6:100*10^-6;
cr    =k1./a;
cf   =k2*d.*a;
ctot   =cr+cf;
plot(a,cr,a,cf,a,ctot)
 title('optimal')
xlabel('cross section area')
ylabel('costs')
legend('cr','ctot','cf')

Answer 1

Do you want the (harder) analytical answer (like from the formula) or the (easier) digital answer from the digitized vectors, like

distances = abs(cf-cr)
[minDistance, indexAtMin] = min(distances);
y1AtMin = cf(indexAtMin)
y2AtMin = cr(indexAtMin)
aAtMin = a(indexAtMin)
hold on;
line([aAtMin, aAtMin], ylim);