trygonometria...

[Aguskaq]

wiedzac ze \(\displaystyle{ sin\alpha}\) + \(\displaystyle{ cos\alpha}\) = \(\displaystyle{ \frac{1}{\sqrt{2}}}\)
to:

|\(\displaystyle{ sin\alpha}\) - \(\displaystyle{ cos\alpha}\)| ??

i drugie wiedzac ze \(\displaystyle{ tg\alpha+ctg\alpha=4}\) oblicz

\(\displaystyle{ tg^{2}\alpha+ctg^{2}\alpha}\) ??

[Vixy]

\(\displaystyle{ (tg\alpha+ctg\alpha)^2-2tg\alpha*ctg\alpha}\)

\(\displaystyle{ tg\alpha=4-ctg\alpha}\)

\(\displaystyle{ 4^2-2*ctg\alpha*(4-ctg\alpha)}\)

[qsiarz]

1. podnies do kwadratu i skorzystaj z jedynki tryg. (sin^2 a + cos^2 a =1)
2. podnies do kwadtaru i zauwaz, ze tg a * ctg a = 1