Pha ban đầu của biên độ tổng hợp

$tg\varphi= \dfrac{{A_1 \sin \varphi _1+ A_2 \sin \varphi _2 }}{{A_1 c{\rm{os}}\varphi _1+A_2 c{\rm{os}}\varphi _2 }}$

$tg\varphi= \dfrac{{A_1c{\rm{os}}\varphi _1+ A_2 c{\rm{os}}\varphi _2 }}{{A_1 \sin \varphi _1+ A_2 \sin \varphi _2 }}$

$tg\varphi= \dfrac{{A_1 c{\rm{os}}\varphi _1-A_2 c{\rm{os}}\varphi _2 }}{{A_1 \sin \varphi _1-A_2 \sin \varphi _2 }}$

$tg\varphi= \dfrac{{A_1\sin \varphi _1- A_2 \sin \varphi_2}}{{A_1c{\rm{os}}\varphi_1- A_2c{\rm{os}}\varphi_2 }}$

$\tan \varphi =\dfrac{{{A}_{1}}\sin {{\varphi }_{1}}-{{A}_{2}}\sin {{\varphi }_{2}}}{{{A}_{1}}co\operatorname{s}{{\varphi }_{1}}+{{A}_{2}}co\operatorname{s}{{\varphi }_{2}}}$ .

$\tan \varphi =\dfrac{{{A}_{1}}\sin {{\varphi }_{1}}+{{A}_{2}}\sin {{\varphi }_{2}}}{{{A}_{1}}co\operatorname{s}{{\varphi }_{1}}-{{A}_{2}}co\operatorname{s}{{\varphi }_{2}}}$.

$\tan \varphi =\dfrac{{{A}_{1}}co\operatorname{s}{{\varphi }_{1}}+{{A}_{2}}co\operatorname{s}{{\varphi }_{2}}}{{{A}_{1}}\sin {{\varphi }_{1}}+{{A}_{2}}\sin {{\varphi }_{2}}}$. 

$\tan \varphi =\dfrac{{{A}_{1}}\sin {{\varphi }_{1}}+{{A}_{2}}\sin {{\varphi }_{2}}}{{{A}_{1}}co\operatorname{s}{{\varphi }_{1}}+{{A}_{2}}co\operatorname{s}{{\varphi }_{2}}}$.