Question

If cosA=0.7? What is A

Answer 1

Answer:

Explanation: Take the inverse cosine of both sides of the equation to extract  A from inside the cosine.

A = arccos ( 0.7 )

Evaluate  

arccos ( 0.7 ) . A

= 0.79539883

The cosine function is positive in the first and fourth quadrants. To find the second solution, subtract the reference angle from  

2π

to find the solution in the fourth quadrant.

A= 2 ( 3.14159265 ) − 0.79539883

Simplify  

2 ( 3.14159265 ) − 0.79539883

A = 5.48778647