Root of a complex function

I would like to find T value when X becomes zero, I tried fzero and failed, could someone show me how can I achieve it

T=500:5:1500;

dQa=(1.21141)*(29.10*10.^-3)*(T-298.15)+(1.158*10.^-5)*(T.^2-298.15^2)/2+(-0.6076*10.^-8)*(T.^3-298.15.^3)/3+(1.311*10.^-12)*(T.^4-298.15.^4)/4;

dQb=(1)*(38.91*10.^-3)*(T-413.15)+(3.904*10.^-5)*(T.^2-413.15^2)/2+(-3.104*10.^-8)*(T.^3-413.15.^3)/3+(8.606*10.^-12)*(T.^4-413.15.^4)/4;

dQc=(8.31490)*(29.00*10.^-3)*(T-298.15)+(0.2199*10.^-5)*(T.^2-298.15^2)/2+(0.5723*10.^-8)*(T.^3-298.15.^3)/3+(-2.871*10.^-12)*(T.^4-298.15.^4)/4;

dQd=-301.912;

X=dQa+dQb+dQc+dQd

Answer 1

[David Hill]

It seens relatively straight forward to solve by brute force. Just keep running while reducing the step size of T until you get the accuracy you desire. I got:

a=min(abs(X));
t=T(find(X==a));%or -a

t=1.204946558342026e3;

[Yusuf Aslan]

Thanks a lot, I appreciate it.