Odpowiedź:
zad 1
A= ( 1, 3)
x = 1 , y = 3
Obliczamy wartość promienia wodzącego
r = √ (x² + y²) = √(1² + 3²) = √(1 + 9) =√10
sinα = y/r = 3/√10 = 3√10/10
cosα = x/r = 1/√10 = √10/10
tgα = y/x = 3/1= 3
ctgα = x/y = 1/3
zad 6
2x² + 7x + 3 = 0
a = 2 , b = 7 , c = 3
Δ = b² - 4ac = 7² - 4 * 2 * 3 = 49 - 24 = 25
√Δ = √25 = 5
x₁ = ( - b - √Δ)/2a = ( - 7 - 5)/4 = - 12/4 = - 3 odrzucamy ponieważ < - 1
x₂ = (- b + √Δ)/2a = (- 7 + 5)/4 = - 2/4 = - 1/2
cosα = - 1/2
