Solve the following equation: `\ 2cos^2theta-5\ costheta+2=0`

Explanation

Let,`2cos^2theta−5costheta+2=0`

⇒`2cos^2theta−4costheta−costheta+2=0`

⇒`2costheta(costheta−2)+(costheta−2)=0`

⇒`(2costheta−1)(costheta−2)=0`

∴ ` costheta=1/2⟶(1) ` or `costheta=2⟶(2)`


Equation (2) is not possible, Since costhetaϵ[−1,1]

From equation (1)

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