SOLUTION: Find the solutions of the given equation in the indicated interval. (Give your answers to two decimal places. Enter your answers as a comma-separated list.) 20 (cos(x))^2 + cos(x)

Algebra ->  Trigonometry-basics -> SOLUTION: Find the solutions of the given equation in the indicated interval. (Give your answers to two decimal places. Enter your answers as a comma-separated list.) 20 (cos(x))^2 + cos(x)      Log On


   



Question 963240: Find the solutions of the given equation in the indicated interval. (Give your answers to two decimal places. Enter your answers as a comma-separated list.)
20 (cos(x))^2 + cos(x) − 1 = 0, [0, π]

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Find the solutions of the given equation in the indicated interval. (Give your answers to two decimal places. Enter your answers as a comma-separated list.)
20 (cos(x))^2 + cos(x) − 1 = 0, [0, π]
20cos^2(x)+cosx-1=0
(5cosx-1)(4cosx+1)=0
..
5cosx-1=0
cosx=1/5
x=1.77
or
4cosx+1=0
cos x=-1/4
x=1.82