SOLUTION: Solve equation for all value of � if � measure in degrees 2cos^2�+2=5cos�

Question 399928: Solve equation for all value of � if � measure in degrees
2cos^2�+2=5cos�

Answer by Tatiana_Stebko(1539) (Show Source): You can put this solution on YOUR website!

make the substitution , x have to be from the interval [-1;1](because cosw always takes values only in the interval[-1;1])

or
or
or
is extraneous root of the equation because it does not belong to the interval [-1;1]
So ,
make the substitution back ,
FORMULA: the solution of eguation is w=+- k is any integer
w=+- k is any integer
w=+- k is any integer
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