Anyone in calculus , where does the fraction in the integral even come from? i've tried to wrap my head around it but it doesnt even make sense nor when i look up on google ( where does fraction behind integral sign come from) get no results\. define where 1/3 is derived from:

{integral sign} x^2*e^x^3 = 1/3 {integral sign} e^x^3*(3x^2) dx = 1/3*e^x^3 + c