Question

If ∆ABC is right angled at C, then the value of cos (A + B) ​

Answer 1

Answer

The value of cos(A + B) is 0

Given

• ∆ABC is right angled at C.

To Find

• The value of cos(A + B)

Solution

Since , ∆ABC is right angled at C

∴ ∠C = 90°

Now we have from angle sum property of a triangle ,

$\sf \implies A + B + C = 180\degree \\\\ \sf\implies A + B + 90\degree = 180\degree \\\\ \sf\implies A+B + 90\degree \\\\ \sf\implies \cos(A + B) = \cos90\degree \\\\ \sf\implies\cos(A +B ) = 0$

Answer 2

Answer

0

Step-by-step explanation:

Refer to the attachment.

#hope it helps...