Question: optimization

I have the following objective function in maple format.in solving it by optimization function I receive non-numeric solution error.also when trying to use heuristics and fsolve function I receive invalid argument error!

r := [int((400*a*(1/a^0.1e-1))*exp(-.1*a)*exp(-0.7e-1*t), t = 0 .. t)+int((400*b*(1/b^0.1e-1))*exp(-.1*b)*exp(-0.7e-1*t), t = t .. 10/n)-(.3*(400*exp(-.1*b)/b^0.1e-1.[10/n-t+0.5e-1*(10/n-t)^(1.5+1)/(1.5+1)]+400*exp(-.1*a)*(1-exp(-0.2e-1*t))/(a^0.1e-1*(0.2e-1))))*((n-1)*(1/2))*exp(-0.7e-1*(10/n))-(.7*400)*exp(-.1*b)*[(1/2)*(10/n-t)^2-0.7e-1*(10/n-t)^3*(1/6)+(0.5e-1*1.5)*(10/n-t)^(1.5+2)/((1.5+1)*(1.5+2))]/b^0.1e-1-90-4*(10/n-t+0.5e-1*(10/n-t)^(1.5+1)/(1.5+1)+400*exp(-.1*a)*(1-exp(-0.2e-1*t))/(a^0.1e-1*(0.2e-1)))-.8*a*(int(400*exp(-.1*a)/a^0.1e-1, t = 0 .. t)-400*exp(-.1*a)*(1-exp(-0.2e-1*t))/(a^0.1e-1*(0.2e-1)))*exp(-0.7e-1*t)-(int((b-1)*((.3*400)*exp(-.1*b)/b^0.1e-1+.8*b)*exp(-0.7e-1*t), t = t .. 10/n))]*(1-exp(-0.7e-1*10))/(1-exp(-0.7e-1*(10/n)))-90*exp(-0.7e-1*10)