Sinx=7/25⇒cosx=-√(1-sin²x)=-√(1-49/625)=-24/25
sint=11/61⇒cost=√(1-sin²t)=√(1-121/3721)=60/61
sin(x+t)=sinxcost+cosxsint=7/25*60/61-24/25*11/61=420/1525-264/1525=
156/1525
sin(x-t)=sin(x+t)=sinxcost-cosxsint=7/25*60/61+24/25*11/61=
=420/1525+264/1525=684/1525
cos(x+t)=cosxcost-sinxsint=-24/25*60/61-7/25*11/61=-1440/1525-77/1525=
=-2211/1525
cos(x-t)=cosxcost+sinxsint=-24/25*60/61+7/25*11/61=
=-1440/1525+77/1525=-669/1225