Question

for triangle ABC prove that : (a+b)cosc + (c+a)cosa (c+a)cosb=a+b+c

Answer 1

$\mathcal{\huge{\purple{\star\:Hayy \: Mate...!! \:\star}}}$

$<I>$
(a+b)cosC +(c+a)cosB+(c+a)cosC = (acosB +bcosA)+(acosC+ccosA)+ (bcosC+ccosB)= a+b+c

projection formulas of properties of traingle :

acosB+bcosA =c acosC+ccosA= b

bcosC+ccosB=a

$<b>$ $<marquee>$ ⭐✌️✌️ HOPE YOU HELP !!