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महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता १२ वी

If y = cosx+cosx+cosx+......∞, show that dydx=sinx1-2y - Mathematics and Statistics

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प्रश्न

If y = `sqrt(cos x + sqrt(cos x + sqrt(cos x + ...... ∞)`, show that `("d"y)/("d"x) = (sin x)/(1 - 2y)`

बेरीज
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उत्तर

y = `sqrt(cos x + sqrt(cos x + sqrt(cos x + ...  ∞)`

∴ y2 = `cos x + sqrt(cos x + sqrt(cos x + ...  ∞)`

∴ y2 = cos x + y

Differentiating w. r. t. x, we get

`2y ("d"y)/("d"x) = -sin x + ("d"y)/("d"x)`

∴ `("d"y)/("d"x)(1 - 2y)` = sin x

∴ `("d"y)/("d"x) = (sin x)/(1 - 2y)`

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पाठ 2.1: Differentiation - Short Answers II

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