Odpowiedź:
zad 1
tgα = 1/5
tg²α = (1/5)² = 1/25
sin²α/cos²α =1/25
25sin²α = cos²α = 1- sin²α
25sin²α + sin²α = 1
26sin²α =1
sin²α = 1/26
sinα = √(1/26) = 1/√26 = √26/26
tgα = sinα/cosα=1/5
5sinα = cosα
cosα = 5 * √26/26 = 5√26/26
zad 2
Korzystamy z twierdzenia sinusów
a/sin45° = 3/sin55°
a : √2/2 = 3 : 0,8192
a * 0,8192 = √2/2 * 3 = 3√2/2
a = 3√2/2 : 0,8192 = 3√2/(2 * 0,8/192) = 3√2/1,6384)
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