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Find k, if the following function is p.d.f. of r.v.X: f(x) = ,for,otherwisekx2(1-x),for 0<x<10,otherwise - Mathematics and Statistics

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प्रश्न

Find k, if the following function is p.d.f. of r.v.X:

f(x) = `{:(kx^2(1 - x)",", "for"  0 < x < 1),(0",", "otherwise"):}`

Find k, if f(x) = `{:(kx^2(1 - x)",", "for"  0 < x < 1),(0",", "otherwise"):}`

is the p.d.f. of random variable X.

बेरीज

उत्तर १

Since f(x) is p.d.f. of r.v.X, we get

`int_-∞^∞ f(x) dx` = 1

∴ `int_-∞^0 f(x)dx + int_0^1 f(x)dx + int_1^∞ f(x)dx` = 1 

∴ `0 + int_0^1 kx^2 (1 - x)dx + 0` = 1

∴ `kint_0^1 (x^2 - x^3)dx` = 1

∴ `k[x^3/3 - x^4/4]_0^1` = 1

∴ `k[(1/3 - 1/4) - 0]` = 1

∴ `k(1/12)` = 1

∴ k = 12

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उत्तर २

Since (x) is the p.d.f. of a r.v. X,

∴ `int_0^1 kx^2 (1 - x) dx = 1`

∴ `int_0^1 k (x^2 - x^3)dx = 1`

`k int_0^1 (x^2 - x^3) dx = 1`

∴ `k{int_0^1 x^2 dx - int_0^1 x^3 dx} = 1`

∴ `k [x^3/3 - x^4/4]_0^1 = 1`

∴ `k(1/12) = 1`

∴ k = 12

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Probability Distribution of a Continuous Random Variable
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