równanie, trygonometria, szereg
: 14 paź 2009, o 23:45
\(\displaystyle{ tgx+tg^{3}x+tg^{5}x...=sin870 \cdot 2^{0,5log _{2}3}}\)
robie to tak:
\(\displaystyle{ \left|tgx \right|<1}\)
\(\displaystyle{ \frac{tgx}{1-(tgx)^{2}}=cos60 \cdot \sqrt{3}}\)
\(\displaystyle{ \frac{tgx}{1-(tgx)^{2}}= \frac{ \sqrt{3} }{2} \left| \cdot 2}\)
\(\displaystyle{ \frac{2tgx}{1-tg^{2}x} = \sqrt{3}}\)
\(\displaystyle{ tg2x= \sqrt{3}}\)
\(\displaystyle{ 2x= \frac{\pi}{3}}\)
\(\displaystyle{ x= \frac{\pi}{6}}\)
prosze o wskazanie błedów
robie to tak:
\(\displaystyle{ \left|tgx \right|<1}\)
\(\displaystyle{ \frac{tgx}{1-(tgx)^{2}}=cos60 \cdot \sqrt{3}}\)
\(\displaystyle{ \frac{tgx}{1-(tgx)^{2}}= \frac{ \sqrt{3} }{2} \left| \cdot 2}\)
\(\displaystyle{ \frac{2tgx}{1-tg^{2}x} = \sqrt{3}}\)
\(\displaystyle{ tg2x= \sqrt{3}}\)
\(\displaystyle{ 2x= \frac{\pi}{3}}\)
\(\displaystyle{ x= \frac{\pi}{6}}\)
prosze o wskazanie błedów