How would you find -LSB- math -RSB- \ tan -LRB- a + b -RRB- = \ dfrac -LCB- \ tan a + \ tan b -RCB- -LCB- 1 - \ tan a \ tan b -RCB- -LSB- / math -RSB- ?
How do you prove tan ^ 2 -LRB- x/2 + pi/4 -RRB- = 1 + sinx/1-sinx ?