1993 - WAEC Mathematics Past Questions and Answers - page 4
If sin x = 12/13, where 0° < x < 90°, find the value of 1 - cos\(^2\)x
\(\sin x = \frac{12}{13}\)
\(\cos x = \frac{5}{13}\)
\(\cos^{2} x = (\frac{5}{13})^2 = \frac{25}{169}\)
\(1 - \cos^{2} x = 1 - \frac{25}{169}\)
= \(\frac{144}{169}\)
The angle of elevation of the top of a tower from a point on the horizontal ground, 40m away from the foot of the tower is 30o. Find the height of the tower.
\(\tan 30 = \frac{x}{40}\)
\(x = 40 \tan 30 = \frac{40}{\sqrt{3}}\)
= \(\frac{40\sqrt{3}}{3} m\)
At a point 500m from the base of a water tank the angle of elevation of the top of the tank is 45o. Find the height of the tank,
\(\tan 45 = \frac{x}{500}\)
\(x = 500 \tan 45\)
= \(500 m\)
Find the median of the following set of numbers: 28, 29, 39, 38, 33, 37, 26, 20, 15, 25
15, 20, 25, 26, 28, 29, 33, 37, 38, 39
median = \(\frac{28 + 29}{2}\)
= 28.5
The table above shows the scores of a group of 40 students in a physics test.
If the mode is m and the median is n, then (m,n) is
The table above shows the scores of a group of 40 students in a physics test
What is the mean of the distribution?
| x | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | Total |
| f | 2 | 3 | 6 | 7 | 9 | 6 | 2 | 2 | 3 | 40 |
| fx | 2 | 6 | 18 | 28 | 45 | 36 | 14 | 16 | 27 | 192 |
Mean = \(\frac{\sum fx}{\sum f}\)
= \(\frac{192}{40}\)
= 4.8
Find the median of the set of numbers 12, 15, 13, 14, 12, 12.
12, 12, 12, 13, 14, 15
Median = \(\frac{12 + 13}{2}\)
= 12.5
The distribution by state of 840 students in the Faculty of Science of a Nigerian University in a certain session is as follows:
| Bendel | 45 |
| kwara | 410 |
| Ogun | 105 |
| Ondo | 126 |
| Oyo | 154 |
In a pie chart drawn to represent this distribution, the angle subtended by Ondo is