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junior college 2 | H2 Maths
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P
P

junior college 2 chevron_right H2 Maths chevron_right Singapore

Can anyone please help? Very much appreciated.

Date Posted: 3 years ago
Views: 339
J
J
3 years ago
Non-negative integers means 0,1,2,3,...

P(X = x) = k(4⁻ˣ)

When x = 0, we have k(4⁻⁰) = k(1/4⁰) = k(1)
= k
When x = 1, we have k(4⁻¹) = k(1/4¹) = k/4
When x = 2, we have k(4⁻²) = k(1/4²) = k/16


We basically have a geometric series with first term k and common ratio ¼

Since |¼| < 1 , the series converges and we can have a sum to infinity.


Since the total probability is 1, the sum of all these probabilities should add up to 1.

i.e S∞ = 1

Using the formula S∞ = a/(1 - r),


k/(1 - ¼) = 1

k = ¾
P
P
3 years ago
Thank you for the very detail explaination. Really appreciated it.
J
J
3 years ago
Welcome

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Tham KY
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J
J
3 years ago
Actually no need to separate the 4⁻⁰ out. The GP can start from it.
Answered in comments.
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J
J's answer
1024 answers (A Helpful Person)