Jaki kąt ?
: 7 wrz 2007, o 21:35
\(\displaystyle{ cos(2\alpha) q -\frac{1}{8}}\) , \(\displaystyle{ sin(\alpha) q \frac{3}{4}}\)
\(\displaystyle{ sin(2\alpha) =?}\)
\(\displaystyle{ sin(2\alpha) =?}\)
\(\displaystyle{ sin^2(\alpha) q \frac{9}{16}}\) (*)
\(\displaystyle{ cos(2\alpha)=cos^2(\alpha)-sin^2(\alpha)}\)
\(\displaystyle{ cos^2(\alpha)+\frac{1}{8} q sin^2(\alpha) q \frac{9}{16}}\)
\(\displaystyle{ cos^2(\alpha) q \frac{7}{16}}\)
a z tego i z (*)
\(\displaystyle{ sin^2(\alpha) = \frac{9}{16}}\) oraz
\(\displaystyle{ cos^2(\alpha) = \frac{7}{16}}\)
dalej sobie poradzisz bez problemów