If cos(B/3) = 1/2(m+1/m) then, prove that: cosB = 1/2(m^3 + 1/m^3)
can't even start pls hlp
Solution:
Given:
To prove:
We'll use the triple angle formula for cosine:
Let , then:
Substituting the given value :
Now, let's expand :
Substituting back:
Hence proved.