Practice China questions with answers and explanations.
By Vieta’s formula, the sum of the roots equals the coefficient 9.
aₙ=a₁+(n−1)d=3+(15−1)×5=73.
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The sum is n(n+1)/2=28, so the mean is 28/7.
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There are 2 favourable outcomes out of 9 equally likely outcomes, so P(red)=2/9.
The coordinate differences are 3 and 4, so the distance is √(3²+4²)=5.
f′(x)=3x²+10x. Substituting x=3 gives 57.
An antiderivative is 2/2 x²+5x. At x=3, the value is 24.0.
The dot product is 2×2+6×4=28.
Rewrite the value using base 3: 27 = 3^3. Matching exponents gives x = 3.
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The sum is n(n+1)/2=21, so the mean is 21/6.
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There are 6 favourable outcomes out of 12 equally likely outcomes, so P(red)=6/12.
The coordinate differences are 3 and 4, so the distance is √(3²+4²)=5.
