Oblicz pozostałe wartości f-cj trygonometrycznych wiedząc że:
1. tg x = 4/3
2. ctg x = 45/28
3. tg x = 2 i x należy (0, 1/2 pi)
4. ctg = 11/60 i x należy (pi, 3/2 pi)
proszę o wytłumaczenie tego zadanie, bo nie umiem na podstawie tg i ctg obliczyc sin i cos. z gory dzieki daje naj ;]
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z.1
tg x = 4/3
tg x = a/b ---> a = 4 oraz b = 3
r^2 = a^2 + b^2 = 4^2 + 3^2 = 16 + 9 = 25
więc r = p(25) = 5
sin x = a/r =4/5
cos x = b/r = 3/5
ctg x = b/a = 3/4
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z.2
ctg x = 45/28
ctg x = b/a ---> a = 28 oraz b = 45
r^2 = a^2 + b^2 = 28^2 + 45^2 = 784 + 2025 = 2 809
r = p(2 809) = 53
sin x = a/r = 28/53
cos x = b/r = 45/53
tg x = 1 / ctg x =28/45
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z.3
tg x = 2 i x należy do ( 0; pi/2 )
tg x = a/b --> a = 2 oraz b = 1
r^2 = a^2 + b^2 = 2^2 + 1^1 = 4 + 1 = 5
r = p(5)
sin x = a/r = 2/p(5)= (2 p(5) )/5
cos x = b/r = 1/p(5) = p(5)/5
ctg x = 1 / tg x = 1/2
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z.4
ctg x =11/60 i x należy do ( pi; (3/2)pi )
ctg x = b/a --> a = -60 oraz b = - 11
r^2 = a^2 + b^2 = (-60)^2 + (-11)^2 = 3600 + 121 = 3721
r = p(3721) = 61
sin x = a/r = -60/61
cos x = b/r = -11/61
tg x = 1/ctg x = 60/11
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p( 5) <-- pierwiastek kwadratowy z 5
P = (a;b) - punkt na II ramieniu kąta
OP = r , gdzie O = (0; 0)
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