how could i sub in the y value to find the x value for the function

k1=0.000358;

k2=0.000158;

ca0=4.89;

x=1:10000;

f = @(x) 0.000358.*4.89.*x./(1+0.000358.*x+0.000158.*x+0.000158*0.000358*x.^2);

g = @(x) 4.89./(1+0.000385.*x);

h = @(x) 4.89.*0.000358.*0.000158.*x.^2/(1+0.000358.*x+0.000158.*x+0.000158.*0.000358*x.^2);

[i,m] = max(f(x))

plot(x,f(x),x,g(x),x,h(x))

legend('cb','ca')

i found the max value i just want to sub it back to the equation to find the x value

Answer 1

[VBBV]

k1=0.000358;
k2=0.000158;
ca0=4.89;
x=1:10000;
f = @(x) 0.000358.*4.89.*x./(1+0.000358.*x+0.000158.*x+0.000158*0.000358*x.^2);
g = @(x) 4.89./(1+0.000385.*x);
h = @(x) 4.89.*0.000358.*0.000158.*x.^2/(1+0.000358.*x+0.000158.*x+0.000158.*0.000358*x.^2);
[i,m] = max(f(x));
plot(x,f(x),x,g(x),x,h(x));
legend('cb','ca') 

x(m)

ans = 4205

[Theeran Kuna]

thanks a lot