Ssc maths

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Two dice are thrown simultaneously. The probability of obtaining a total score of 5 is

Two dice are thrown simultaneously. The probability of obtaining a total score of 5 is

Solutions:

Total number of case that can take place = 6^2 = 36

And event of getting a total score of 5 = {(1,4)(2,3)(4,1)(3,2)}

Favorable case = 4

Probability = 4/36 = 1/9

 

13th March 2019

vitorr maths

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If x^4 + 1/x^4 = 727, then find the value of x^3 - 1/x^3

If x^4 + 1/x^4  = 727, then find the value of  x^3 - 1/x^3 


Solution:

Adding 2 to both sides,

x^4 + 1/x^4  + 2 = 727 + 2 

x^4 + 1/x^4  + 2. x^4.  1/x^4  = 729

〖(x^2+ 1/x^2 )〗^2 = 〖27〗^2

x^2+  1/x^2  = 27

Subtracting 2 to both sides:

x^2+  1/x^2  - 2 = 27 + 2

x^2 + 1/x^2  - 2. x^2.  1/x^2  = 25

〖(x- 1/x)〗^2 = 5^2

x-  1/x = 5

Cubing both sides:

〖(x- 1/x)〗^3 = 5^3

x^3 - 1/x^3  -3(x-  1/x) = 125

x^3 - 1/x^3  -3*5 = 125

x^3 - 1/x^3  = 125 +15 = 140



07th March 2019

vitorr maths

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