Answer each of the following questions in one word or one sentence or as per exact requirement of the question: Write the principal value of cos –1 (cos 680°).

Question

Philoid · Accepted Answer

Given cos^-1 (cos 680°)

= cos^-1 (cos (720° - 40°))

= cos^-1 (cos (2 × 360° - 40°))

= cos^-1 (cos 40°)

= 40°

∴ cos^-1 (cos 680°) = 40°

Answer each of the following questions in one word or one sentence or as per exact requirement of the question:Write the principal value of cos–1(cos 680°).

Answer each of the following questions in one word or one sentence or as per exact requirement of the question:
Write the principal value of cos^–1(cos 680°).