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Kat α jest ostry i spelnia warunek sinα= [tex]\frac{\sqrt{2} }{3}[/tex] oblicz [tex]\frac{sin\alpha }{1+cos\alpha }[/tex] + [tex]\frac{cos\alpha }{sin\alpha }[/tex]

daje naj proszę o obliczenia :)


Odpowiedź :

Odpowiedź:

sinα = √2/3

sin²α = (√2/3)² = 2/9

1 - cos²α = 2/9

cos²α = 1 - 2/9 = 7/9

cosα = √(7/9) = √7/3

sinα/(1 + cosα) + cosα/sinα = √2/3 : (1 + √7/3) + √7/3 : √2/3 =

= √2/3(1 + √7/3) + √7/3 * 3/√2 = √2/(3 + √7) + √7/√2 =

= √2(3 - √7)/[(3 + √7)(3 - √7)] + √7/√2 =

= √2(3 - √7)/(9 - 7) + √7/√2 = √2(3 - √7)/2 + √7 * √2/2 =

= √2(3 - √7)/2 + √14/2 = [3√2 - √(2 * 7)  + √14]/2 =

= (3√2 - √14 + √14)/2 = 3√2/2