If veca+vecb+vecc "and " a^(2)+b^(2)=c^(2), the angle between the vectors vecc"and "veca is

If veca+vecb+vecc "and " a^(2)+b^(2)=c^(2), the angle between the vect

1.	If veca+vecb+vecc "and " a^(2)+b^(2)=c^(2), the angle between the vectors vecc"and "veca is
Answer» ANSWER :`TAN^(-1)(b/a)`