ECAT · Mathematics · 9 questions
Name: ____________________ Date: ____________
What are the roots of x² - 5x + 6 = 0?
What is the sum of the roots of 2x² - 7x + 3 = 0?
For which values of k does x² + kx + 9 = 0 have equal roots?
What is the 10th term of the arithmetic progression 3, 7, 11, ...?
What is the sum of the first 10 terms of the geometric progression 1, 2, 4, 8, ...?
What is the coefficient of x² in the expansion of (1 + x)⁵?
If f(x) = 2x + 3, then the inverse function f⁻¹(x) is:
What is the domain of f(x) = sqrt(x - 4)?
What is the sum to infinity of the series 1 + 1/2 + 1/4 + 1/8 + ...?
1. A, 2. A, 3. D, 4. A, 5. D, 6. C, 7. C, 8. C, 9. A
Factorise as (x - 2)(x - 3) = 0, so x = 2 or x = 3.
For ax² + bx + c = 0 the sum of the roots is -b/a = 7/2.
Equal roots need discriminant zero: k² - 36 = 0, so k = 6 or k = -6.
The nth term is a + (n - 1)d = 3 + 9 x 4 = 39.
S = a(r^n - 1) / (r - 1) = (2¹⁰ - 1) / 1 = 1023.
The coefficient is 5C2 = 10.
Let y = 2x + 3. Then x = (y - 3) / 2, so f⁻¹(x) = (x - 3) / 2.
The expression under the square root must be at least zero, so x - 4 >= 0 and x >= 4.
S = a / (1 - r) = 1 / (1 - 1/2) = 2.