SOLUTION: Find exact solutions over the indicated interval for x. If necessary, express your solution in terms of k where k is any integer. the square root of 2 times cosx + 1 = 0. 0is less

Algebra ->  Trigonometry-basics -> SOLUTION: Find exact solutions over the indicated interval for x. If necessary, express your solution in terms of k where k is any integer. the square root of 2 times cosx + 1 = 0. 0is less      Log On


   

Question 854451: Find exact solutions over the indicated interval for x. If necessary, express your solution in terms of k where k is any integer. the square root of 2 times cosx + 1 = 0. 0is less than or equal to x and x is less than 2 pi.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Find exact solutions over the indicated interval for x. If necessary, express your solution in terms of k where k is any integer. the square root of 2 times cosx + 1 = 0. 0is less than or equal to x and x is less than 2 pi.
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sqrt(2)cos(x) + 1 = 0
cos(x) = -1/sqrt(2)
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x = arccos(-sqrt(2)/2))
Reference angle pi/4
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Since cos is negative,
x = (3/4)pi in QII
OR
x = (5/4)pi in QIII
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cheers,
Stan H
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