Solution 4.4:1d
From Förberedande kurs i matematik 1
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| - | {{  | + | Because   | 
| - | <  | + | <math>\tan v=\frac{\sin v}{\cos v}</math>, the condition   | 
| - | {{  | + | <math>\text{tan }v=\text{1 }</math>  | 
| + | gives   | ||
| + | <math>\text{sin }v=\text{ cos }v</math>, i.e. we look for angles in the unit circle whose   | ||
| + | <math>x</math>  | ||
| + | - and   | ||
| + | <math>y</math>  | ||
| + | -coordinates are equal.  | ||
| + | |||
| + | After drawing the unit circle and the line y=x, we see that there are two angles which satisfy these conditions,   | ||
| + | <math>v={\pi }/{4}\;</math>  | ||
| + | and   | ||
| + | <math>v=\pi +{\pi }/{4}\;={5\pi }/{4}\;</math>  | ||
| + | |||
| + | |||
[[Image:4_4_1_d.gif|center]]  | [[Image:4_4_1_d.gif|center]]  | ||
Revision as of 12:38, 30 September 2008
Because \displaystyle \tan v=\frac{\sin v}{\cos v}, the condition \displaystyle \text{tan }v=\text{1 } gives \displaystyle \text{sin }v=\text{ cos }v, i.e. we look for angles in the unit circle whose \displaystyle x - and \displaystyle y -coordinates are equal.
After drawing the unit circle and the line y=x, we see that there are two angles which satisfy these conditions, \displaystyle v={\pi }/{4}\; and \displaystyle v=\pi +{\pi }/{4}\;={5\pi }/{4}\;

