Find the sum of the first 20 terms of the sequences, -7, - 3, 1, . . . . . 

If tan x = \(\frac{1}{3}\), where 180º < x < 270º

evaluate \(\frac{sin2 x - cos x}{2 tan x + sin 2x}\), leaving the answer in surd form (radicals)

Find the sum of all natural numbers between 403 and 603 which are divisible by 7

Using the trapezium rule with seven ordinates, evaluate, correct to three decimal places, \(\int_{2.4}^{3.6} \frac{1}{\sqrt{x^2 - 2}}\)dx

Find the equation of the normal to the curve y = 7x - 5x\(^2\) at x = 2