SOLUTION: Solve the equation on the given interval, expressing the solution for x in terms of inverse trigonometric functions. (Enter your answers as a comma-separated list.) 7(cos x)^2 &#

Algebra ->  Trigonometry-basics -> SOLUTION: Solve the equation on the given interval, expressing the solution for x in terms of inverse trigonometric functions. (Enter your answers as a comma-separated list.) 7(cos x)^2 &#      Log On


   



Question 735214: Solve the equation on the given interval, expressing the solution for x in terms of inverse trigonometric functions. (Enter your answers as a comma-separated list.)
7(cos x)^2 − cos x − 6 = 0 on [π/2, π]
Thank you!

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Solve the equation on the given interval, expressing the solution for x in terms of inverse trigonometric functions. (Enter your answers as a comma-separated list.)
7(cos x)^2-cos x−6=0 on [π/2, π]
..
7(cos x)^2-cos x−6=0
(7cosx+6)(cosx-1)=0
..
7cosx+6=0
7cosx=-6
cosx=-6/7
x=arccos(-6/7)
..
cosx-1=0
cosx=1
x=arccos(1)
..
solutions: x=arccos(-6/7), arccos(1)