Find the two standard angles between 0° and 360° whose cosine...

Question

a) Find the two standard angles between 0° and 360° whose cosine value is -0.7. Round your answer to 1 decimal place.

 

b) Find the two standard angles between 0° and 360° whose tangent value is 10. Round your answer to 1 decimal place.

Answer 1

A)  the inverse cosine function on your calculator will give you 134.4°, but this is only one of the two angles that have that cosine, the other is its reflection across the x-axis 360º - 134.4° = 225.6°.

 

b)  the Arctan function on your calculator will give you 84.3°.  Again, this is only one of two values, the other is its reflection across the origin.

84.3º + 180º = 224.3º