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Topic Content:
- Special Angles
45°
Consider an Isosceles right-angled triangle of equal sides of 1 unit each and hypotenuse side \( \scriptsize \sqrt {2}\)units.
- sin 45° = \( \frac {1}{\sqrt {2}}\)
- cos 45° = \( \frac {1}{\sqrt {2}}\)
- tan 45° = \( \frac {1}{1} = \scriptsize 1\)
30° and 60°
Consider an equilateral ∆ of side 2 units.
- sin 30° = \( \frac {1}{2}\)
- cos 30° = \( \frac {\sqrt {3}}{2}\)
- tan 30° = \( \frac {1}{\sqrt {3}}\)
- sin 60° = \( \frac {\sqrt {3}}{2}\)
- cos 60° = \( \frac {1}{2}\)
- tan 60° = \( \frac {\sqrt {3}}{1}\)
Recall,
1) sin 45° = cos 45° = \( \frac {1}{\sqrt {2}}\)
2) sin 30° = cos 60° = \( \frac {1}{2}\)
3) sin 60° = cos 30° = \( \frac {\sqrt {3}}{2}\)
4) tan 30° = \( \frac {1}{tan 60°}\)
Example 6.3.1:
In the figures in a , b and c
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