Given that \(y = 4 - 9x\) and \(\Delta x = 0.1\), calculate \(\Delta y\).
Four fair coins are tossed once. Calculate the probability of having equal heads and tails.
In calculating the mean of 8 numbers, a boy mistakenly used 17 instead of 25 as one of the numbers. If he obtained 20 as the mean, find the correct mean.
Simplify: \(^{n}C_{r} ÷ ^{n}C_{r-1}\)
If \(2\sin^{2} \theta = 1 + \cos \theta, 0° \leq \theta \leq 90°\), find the value of \(\theta\).
