Lösung 4.4:3c
Aus Online Mathematik Brückenkurs 1
K (Lösning 4.4:3c moved to Solution 4.4:3c: Robot: moved page) |
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- | {{ | + | If we consider the entire expression |
- | < | + | <math>x+\text{4}0^{\circ }</math> |
- | {{ | + | as an unknown, we have a fundamental trigonometric equation and can, with the aid of the unit circle, see that there are two solutions to the equation for |
+ | <math>0^{\circ }\le x+\text{4}0^{\circ }\le \text{36}0^{\circ }</math> | ||
+ | namely | ||
+ | <math>x+\text{4}0^{\circ }=\text{65}^{\circ }</math> | ||
+ | and the symmetric solution | ||
+ | <math>x+\text{4}0^{\circ }=\text{18}0^{\circ }-\text{65}^{\circ }=\text{115}^{\circ }</math>. | ||
[[Image:4_4_3_c.gif|center]] | [[Image:4_4_3_c.gif|center]] | ||
+ | |||
+ | It is then easy to set up the general solution by adding multiples of | ||
+ | <math>360^{\circ }</math>, | ||
+ | |||
+ | |||
+ | <math>x+\text{4}0^{\circ }=\text{65}^{\circ }+n\centerdot 360^{\circ }</math> | ||
+ | and | ||
+ | <math>x+\text{4}0^{\circ }=\text{115}^{\circ }+n\centerdot 360^{\circ }</math> | ||
+ | |||
+ | |||
+ | for all integers | ||
+ | <math>n</math>, which gives | ||
+ | |||
+ | |||
+ | <math>x=2\text{5}^{\circ }+n\centerdot 360^{\circ }</math> | ||
+ | and | ||
+ | <math>x=7\text{5}^{\circ }+n\centerdot 360^{\circ }</math> |
Version vom 09:50, 1. Okt. 2008
If we consider the entire expression \displaystyle x+\text{4}0^{\circ } as an unknown, we have a fundamental trigonometric equation and can, with the aid of the unit circle, see that there are two solutions to the equation for \displaystyle 0^{\circ }\le x+\text{4}0^{\circ }\le \text{36}0^{\circ } namely \displaystyle x+\text{4}0^{\circ }=\text{65}^{\circ } and the symmetric solution \displaystyle x+\text{4}0^{\circ }=\text{18}0^{\circ }-\text{65}^{\circ }=\text{115}^{\circ }.
It is then easy to set up the general solution by adding multiples of \displaystyle 360^{\circ },
\displaystyle x+\text{4}0^{\circ }=\text{65}^{\circ }+n\centerdot 360^{\circ }
and
\displaystyle x+\text{4}0^{\circ }=\text{115}^{\circ }+n\centerdot 360^{\circ }
for all integers
\displaystyle n, which gives
\displaystyle x=2\text{5}^{\circ }+n\centerdot 360^{\circ }
and
\displaystyle x=7\text{5}^{\circ }+n\centerdot 360^{\circ }