Nierówności trygonometryczne
: 26 mar 2012, o 17:26
Jeżeli \(\displaystyle{ \alpha >0 , \beta >0}\) i \(\displaystyle{ \alpha + \beta < \frac{ \pi }{4}}\) to
A: \(\displaystyle{ \ctg 2 \alpha + \ctg 2 \beta < 2\ctg ( \alpha + \beta )}\)
B: \(\displaystyle{ \ctg 2 \alpha + \ctg 2 \beta \ge 2\ctg ( \alpha + \beta )}\)
C: \(\displaystyle{ \ctg \frac{ \pi }{7} + \ctg \frac{ \pi }{7} \ge 2\ctg \frac{ \pi }{5}}\)
D: \(\displaystyle{ \ctg \frac{ \pi }{7} + \ctg \frac{ \pi }{7} < 2\ctg \frac{ 2\pi }{7}}\)
A: \(\displaystyle{ \ctg 2 \alpha + \ctg 2 \beta < 2\ctg ( \alpha + \beta )}\)
B: \(\displaystyle{ \ctg 2 \alpha + \ctg 2 \beta \ge 2\ctg ( \alpha + \beta )}\)
C: \(\displaystyle{ \ctg \frac{ \pi }{7} + \ctg \frac{ \pi }{7} \ge 2\ctg \frac{ \pi }{5}}\)
D: \(\displaystyle{ \ctg \frac{ \pi }{7} + \ctg \frac{ \pi }{7} < 2\ctg \frac{ 2\pi }{7}}\)