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9 سوالات: ای کیٹ ریاضی، جوابات اور وضاحت کے ساتھ۔
What are the roots of x^2 - 5x + 6 = 0?
درست جواب: 2 and 3
Factorise as (x - 2)(x - 3) = 0, so x = 2 or x = 3.
What is the sum of the roots of 2x^2 - 7x + 3 = 0?
درست جواب: 7/2
For ax^2 + bx + c = 0 the sum of the roots is -b/a = 7/2.
For which values of k does x^2 + kx + 9 = 0 have equal roots?
درست جواب: k = 6 or -6
Equal roots need discriminant zero: k^2 - 36 = 0, so k = 6 or k = -6.
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 x^2 in the expansion of (1 + x)^5?
If f(x) = 2x + 3, then the inverse function f^-1(x) is:
درست جواب: (x - 3) / 2
Let y = 2x + 3. Then x = (y - 3) / 2, so f^-1(x) = (x - 3) / 2.
What is the domain of f(x) = sqrt(x - 4)?
درست جواب: x >= 4
The expression under the square root must be at least zero, so x - 4 >= 0 and x >= 4.
What is the sum to infinity of the series 1 + 1/2 + 1/4 + 1/8 + ...?