Processing Math: Done
Solution 4.2:5d
From Förberedande kurs i matematik 1
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- | {{ | + | By subtracting |
- | < | + | <math>360^{\circ }</math> |
- | {{ | + | from |
+ | <math>\text{495}^{\circ }</math>, we do not change the value of the tangent: | ||
+ | |||
+ | |||
+ | <math>\tan \text{495}^{\circ }=\tan \left( \text{495}^{\circ }-360^{\circ } \right)=\tan \text{135}^{\circ }</math> | ||
+ | |||
+ | We know from exercise a that | ||
+ | <math>\cos 135^{\circ }=-\frac{1}{\sqrt{2}}</math> | ||
+ | and | ||
+ | <math>\sin 135^{\circ }=\frac{1}{\sqrt{2}}</math>, which gives | ||
+ | |||
+ | |||
+ | <math>\tan 135^{\circ }=\frac{\sin 135^{\circ }}{\cos 135^{\circ }}=\frac{\frac{1}{\sqrt{2}}}{-\frac{1}{\sqrt{2}}}=-1</math> |
Revision as of 08:16, 29 September 2008
By subtracting
=tan
495
−360
=tan135
We know from exercise a that
=−1
2
=1
2
=sin135
cos135
=1
2−1
2=−1