Question

please help
if in a triangle ABC 8(cosA)(cosB)(cosC)=1
prove that the triangle is equilateral

Answer 1

if it is an euilateral triangle then it has all the measure angles are 60 degrees.
A< = <B = <C = 60
you just show that 8 * cos(60) * cos(60) * cos(60) = 1

Answer 2

can we do it in some other way?

Answer 3

by using contradiction,
show that 8 * cos(60) * cos(60) * cos(60) not equal 1