Practice China questions with answers and explanations.
By Vieta’s formula, the sum of the roots equals the coefficient 18.
aₙ=a₁+(n−1)d=5+(8−1)×4=33.
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The sum is n(n+1)/2=36, so the mean is 36/8.
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There are 6 favourable outcomes out of 12 equally likely outcomes, so P(red)=6/12.
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The sum is n(n+1)/2=28, so the mean is 28/7.
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There are 5 favourable outcomes out of 10 equally likely outcomes, so P(red)=5/10.
The coordinate differences are 3 and 4, so the distance is √(3²+4²)=5.
f′(x)=12x²+10x. Substituting x=3 gives 138.
An antiderivative is 3/2 x²+4x. At x=4, the value is 40.0.
Subtract 5 from both sides and divide by 5: x = (35-5)/5 = 6.
By Vieta’s formula, the sum of the roots equals the coefficient 15.
aₙ=a₁+(n−1)d=4+(7−1)×3=22.
