hello everyone. i have a probelm while making my code..

i have to fit the theoritical data to experimental data. now there is one probelm.the theoritcal data (p_T) can't fit well to experimental data so i treat the (p_T) as f_0(p_T)=kf1(p_T1)+(1-k)f2(p_T2). actually pt range is 4.5 GeV. but i by treating the mentioned treatment i did seperately f1(p_T1) and f2(p_T2).they both are working.f1(p_T1) fits the initial points of the data while f2(p_T2) fits the reaming data.but now i don't know how to make them in one code. i can share my both codes which i did seperately...