Trigonometry

Answer all the questions below and press submit to see how many you got right.

id: 15217

$\cos 0^{\circ}=?$

id: 15200
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Given is a right triangle that has a hypotenuse of length $c.$ One of the other angles is $\alpha$ and the leg opposite to this angle has length $a.$ Then we define $\sin \alpha:=\frac{a}{c}.$ Why is this definition independent of the specific triangle?

  • There is only one triangle like this.
    The definition actually depends on the specific nature of the triangle.
    All right triangles that share another angle are similar and ratios of corresponding sides of similar triangles are the same.
    All triangles that share two angles are congruent. Because of that their sides are the same.
id: 15210
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Given is a right triangle that has a hypotenuse of length 1. One of the other angles is $\alpha$ and the leg opposite to this angle has length $a.$ Then $a=?$

  • $\tan \alpha$
    $\cot \alpha$
    $\cos \alpha$
    $\sin \alpha$