Question

If 2cos^2x + 7sinx = 5 find the permissible value of sin x??
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Answer 1

Answer:

1/2

Step-by-step explanation:

2(1-sin^2x)+7sinx=5

2-2sin^2x+7sinx=5

2sin^2x-7sinx-2=-5

2sin^2x-7sinx-2+5=0

2sin^2x-7sinx+3=0

let take sinx=a

so 2a^2-7a+3=0

2a^2-6a-a+3=0

2a(a-3)-1(a-3)=0

(2a-1)(a-3)=0

2a-1=0 or a-3=0

a=3

it's not possible why because the maximum value of sin is 1

so 2a-1=0

2a=1

a=1/2

so sinx=1/2