Question

) Cos 40 +
+ Cos 50+ Cos 70+ Cos80
= Cos 20 + Cos 10​

Answer 1

Step-by-step explanation:

Cos 40 + Cos 50+ Cos 70+ Cos80 = Cos 20 + Cos 10

cos 40 = 0.7660444431

cos 50 = 0.6427876097

cos 70 = 0.3420201433

cos 80 = 0.1736481777

cos 10 = 0.984807753

cos 20 = 0.9396926208

putting the above values in the question we get,

0.7660444431 + 0.6427876097 + 0.3420201433 + 0.1736481777 = 0.984807753 + 0.9396926208

=》 1.9245003738 = 1.9245003738

HENCE PROVED...