Verify that the x values are solutions of the equation. How do I do this? 2 cos^2x+3cosx+1=0 x=4pi/3 x=pi

1 Answer
Jim G.
Feb 27, 2018

#"see explanation"#

Explanation:

#"substitute the given solutions into the equation and if"#
#"the equation is true then they are solutions"#

#"consider left side with "x=(4pi)/3#

#2(cos((4pi)/3))^2+3cos((4pi)/3)+1#

#=2xx(-1/2)^2+(3xx-1/2)+1#

#=1/2-3/2+1=0=" right side"#

#rArrx=(4pi)/3" is a solution of the equation"#

#"consider left side with "x=pi#

#2(cospi)^2+3cospi+1#

#2xx(-1)^2+(3xx-1)+1=2-3+1=0=" right "#

#rArrx=pi" is a solution of the equation"#

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