SOLUTION: PLEASE HELP ME SOLVE THIS TRIGONOMETRIC FUNCTIONS: cos(-140degree) there are the three poossible anwers a)cos(-40degree) b)-cos 40degree c)cos 40degree

Algebra ->  Trigonometry-basics -> SOLUTION: PLEASE HELP ME SOLVE THIS TRIGONOMETRIC FUNCTIONS: cos(-140degree) there are the three poossible anwers a)cos(-40degree) b)-cos 40degree c)cos 40degree      Log On


   

Question 236960: PLEASE HELP ME SOLVE THIS TRIGONOMETRIC FUNCTIONS:
cos(-140degree)
there are the three poossible anwers
a)cos(-40degree)
b)-cos 40degree
c)cos 40degree
Answer by solver91311(24713) About Me  (Show Source):
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is positive in Quadrant I and IV. 40 degrees is in QI, -40 degrees is in QIV. Therefore , and answer a and c are the same answer. b is the only one that is different, so it has to be correct.

John