trig question

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Compute inverse functions to four significant digits.
cos^2x=3-5cosx


cos^2x + 5cosx -3=0

now you have a quadratic, solve for cos x using the equation

cosx=(-5 -+ sqrt (25 +12)/2

the back of the book says .9987+2kpi and -.09987+2kpi

when i do it i don't get that answer.


I get it, that answer is in radians. The 2kpi is to keep rotation a number of times in the circle.

Thank you so much for helping me I have AC tomorrow and without your help i would have not been able to do that whole section.

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