Postgraduate Mathematics II task 38: The roots of x² − 7x + 12 = 0 are r and s. Enter r+s.
By Vieta’s formula, the sum of the roots equals the coefficient 7.
Practice Mathematics II questions with answers and explanations.
By Vieta’s formula, the sum of the roots equals the coefficient 7.
Rewrite the value using base 2: 4 = 2^2. Matching exponents gives x = 2.
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Use the circle-area formula A = πr². Substituting r = 2 gives A = π × 2² = 4π.
An antiderivative is 1/2 x²+1x. At x=2, the value is 4.0.
The dot product is 1×3+2×5=13.
By Vieta’s formula, the sum of the roots equals the coefficient 13.
aₙ=a₁+(n−1)d=6+(9−1)×5=46.
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The sum is n(n+1)/2=45, so the mean is 45/9.
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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+14x. Substituting x=1 gives 17.
The coordinate differences are 3 and 4, so the distance is √(3²+4²)=5.