Given that r = (10 N , 200°) and n = (16 N , 020°),
FURTHER MATHEMATICS
WAEC 2023
Given that r = (10 N , 200°) and n = (16 N , 020°), find (3r - 2n).
- A. (62 N , 240°)
- B. (62 N , 200°)
- C. (62 N , 280°)
- D. (62 N , 020°)
Correct Answer: D. (62 N , 020°)
Explanation
r = (10 N, 200º) and n = (16 N, 020º)
In rectangular form:
r = 10cos 200ºi + 10sin 200ºj = -9.397i - 3.420j
n = 16cos 20ºi + 16sin 20ºj = 15.035i + 5.472j
3r = -28.191i - 10.260j
2n = 30.070i + 10.945j
3r - 2n = (-28.191i - 10.260j) - (30.070i + 10.945j)
3r - 2n = -58.261i - 21.205j
|3r - 2n| = √((-58.261)\(^2\) + (-21.205)\(^2\)) = 62 N
\(tan θ =\frac{-21.205}{-58.261} = 0.3640\)
\(θ = tan^{-1} (0.3640) = 20^o\)
∴ (62 N , 020º)
Post an Explanation Or Report an Error
If you see any wrong question or answer, please leave a comment below and we'll take a look. If you doubt why the selected answer is correct or need additional more details? Please drop a comment or Contact us directly. Your email address will not be published. Required fields are marked *