trong>
75°
81°
85°
Correct answer is C
\(\overrightarrow{x} . \overrightarrow{y} = |\overrightarrow{x}||\overrightarrow{y}|\cos\theta\)
\(\overrightarrow{x} . \overrightarrow{y} = (i - 3j) . (6i + j) = 6 - 3 = 3\)
\(|\overrightarrow{x}| = \sqrt{1^{2} + (-3)^{2}} = \sqrt{10}\)
\(|\overrightarrow{y}| = \sqrt{6^{2} + 1^{2}} = \sqrt{37}\)
\(\therefore 3 = (\sqrt{10})(\sqrt{37})\cos \theta\)
\(\cos\theta = \frac{3}{\sqrt{370}} = 0.1559\)
\(\theta = \cos^{-1} 0.1559 \approxeq 81°\)
If sin x = \(\frac{12}{13}\) and sin y = \(\frac{4}{5}\), where x and y are acute angles, find&...
If the midpoint of the line joining (1 - k, -4) and (2, k + 1) is (-k, k), find the value of k. ...
The inverse of a function is given by \(f^{-1} : x \to \frac{x + 1}{4}\)....
Marks 2 3 4 5 6 7 8 No of students 5 7 9 6 3 6 4 The table above sho...
Find the equation of a circle with centre (2, -3) and radius 2 units. ...