Express \(r = (12, 210°)\) in the form \(a i + b j\).
\(6(-i + \sqrt{3} j)\)
\(6(-\sqrt{3} i - j)\)
\(6(i - \sqrt{3} j)\)
\(6(i + \sqrt{3} j)\)
Correct answer is B
\(F = F \cos \theta i + F \sin \theta j\)
\(r = (12, 210°) = 12 \cos 210 i + 12 \sin 210 j\)
= \(- 6\sqrt{3} i - 6j\)
= \(6(-\sqrt{3} i - j)\)
| Marks | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| No of students | 5 | 7 | 9 | 6 | 3 | 6 | 4 |
The table above shows the distribution of marks by some candidates in a test. If a student is selected at random, what is the probability that she scored at least 6 marks?
\(\frac{3}{40}\)
\(\frac{1}{4}\)
\(\frac{13}{40}\)
\(\frac{27}{40}\)
Correct answer is C
No explanation has been provided for this answer.
| Marks | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| No of students | 5 | 7 | 9 | 6 | 3 | 6 | 4 |
The table above shows the distribution of marks by some candidates in a test. Find, correct to one decimal place, the mean of the distribution.
5.5
5.3
5.2
4.7
Correct answer is D
| Marks(\(x\) | 2 | 3 | 4 | 5 | 6 | 7 | 8 | Total |
| Frequency \(f\) | 5 | 7 | 9 | 6 | 3 | 6 | 4 | 40 |
| \(fx\) | 10 | 21 | 36 | 30 | 18 | 42 | 32 | 189 |
Mean \(\bar{x} = \frac{\sum fx}{\sum f} = \frac{189}{40}\)
= \(4.725 \approxeq 4.7\)
| Marks | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| No of students | 5 | 7 | 9 | 6 | 3 | 6 | 4 |
The table above shows the distribution of marks by some candidates in a test. What is the median score?
3.5
4.0
4.5
5.0
Correct answer is B
No explanation has been provided for this answer.
(3 N, 020°)
(3 N, 200°)
(17 N, 020°)
(17 N, 200°)
Correct answer is A
No explanation has been provided for this answer.