Practice china-kaoyan-math-1 questions with answers and explanations.
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Use the circle-area formula A = πr². Substituting r = 4 gives A = π × 4² = 16π.
Percentage=(11/46)×100=23.91.
Subtract 3 from both sides and divide by 8: x = (51-3)/8 = 6.
By Vieta’s formula, the sum of the roots equals the coefficient 8.
aₙ=a₁+(n−1)d=2+(8−1)×4=30.
f′(x)=6x²+14x. Substituting x=3 gives 96.
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Use the circle-area formula A = πr². Substituting r = 3 gives A = π × 3² = 9π.
Percentage=(10/45)×100=22.22.
Subtract 11 from both sides and divide by 7: x = (46-11)/7 = 5.
By Vieta’s formula, the sum of the roots equals the coefficient 14.
aₙ=a₁+(n−1)d=10+(7−1)×3=28.
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The sum is n(n+1)/2=45, so the mean is 45/9.
