Practicing Success
Practicing Success
CUET Preparation Today
In a right-angled triangle ABC, sin(A+B) = 1 and cos A = \(\frac{1}{2}\), find value of cos (C-B)? |
\(\frac{1}{2}\) 1 \(\frac{\sqrt {3 }}{2}\) \(\frac{1}{\sqrt {2}}\) |
\(\frac{1}{2}\) |
sin(A+B) = 1 ⇒ A+B = 90° cosA = \(\frac{1}{2}\) ⇒ A = 60° ⇒ B = 30° ⇒ A + B + C = 180° ⇒ (60° + 30°) + C = 180° ⇒ C = 90° ∴ cos (C-B) = cos (90° - 30°) = cos60° = \(\frac{1}{2}\) |
