Question

if 2 cos square theta - 11 cos theta + 5 is equal to zero then find possible value of cos theta​

Answer 1

Answer:

cosθ = 1/2

Step-by-step explanation:

2cos²θ - 11cosθ + 5 = 0

2cos²θ - cosθ - 10cosθ + 5 = 0

cosθ(2cosθ - 1) -5(2cosθ - 1) = 0

(cosθ - 5)(2cosθ - 1) = 0

cosθ = 5 or cosθ = 1/2

cosθ = 5 is not possible since cosθ can only have values from -1 to +1

Thus, cosθ = 1/2

Answer 2

Step-by-step explanation:

let cos thita be X

now,

2x^2-11x +5=0

2x(x-5) -1(x-5)=0

(x-5)(2x-1)=0

X=5,1/2

so, cos thita =1/2 only

because range of cos thita is -1 to 1

so, 5 will be rejected...

hope it helps.!!......if u r satisfied....

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