Question

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

Answer 1

• $\bf \large\underline{Given : }$

∆ABC is right angled at C.

• $\bf \large\underline{Find : }$

The value of cos(A + B)

• $\bf \large\underline{Solution : }$

Since , ∆ABC is right angled at C

∴ ∠C = 90°

→ A + B + C = 180

→ A + B + 90

→ cos ( a + b ) = cos 90°

→ cos ( a+ b ) = 0