1. Real-number and algebraic structure
15 marks
This question uses exact arithmetic, inequalities, binomial coefficients, and summation notation.
(a)
3 marks
Prove that \(\sqrt{3}+\sqrt{7}\) is irrational.
(b)
4 marks
Solve the inequality \(\frac{2x+1}{x-3}\ge1\).
(c)
4 marks
Find the coefficient of \(x^5\) in the expansion of \((2-x)^7\).
(d)
4 marks
Evaluate \(\sum_{r=1}^{10}(2r^2-r)\).