The solution of 2cos2x + cosx − 1 = 0 is [tex]x=\pi.[/tex]
What is a Trigonometric equation?
A Trigonometric equation is an equation involving one or more trigonometric ratios of unknown angles.
How to solve?
2cos2x + cosx − 1 = 0
[tex]-3+\cos \left(x\right)+4\cos ^2\left(x\right)=0[/tex]
[tex]\cos \left(x\right)=\frac{3}{4},\:\cos \left(x\right)=-1[/tex]
And now,
[tex]x=\pi +2\pi n[/tex]
Which is only [tex]x=\pi[/tex].
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