Find the value of Tan 19π/4?

1 Answer
Apr 25, 2018

#tan((19pi)/4)=-1#

Explanation:

We note that,

#color(blue)(pi-theta,3pi-theta,5pi-theta,...,(2k+1)pi-theta,toII^(nd) Quadrant#

#color(blue)(So, tantheta < 0#

#color(blue)(=>tan(pi-theta)=tan(3pi-theta)=tan(5pi-theta)=...=- tantheta#

We have,

#tan((19pi)/4)=tan((20pi-pi)/4)=tan((20pi)/4-pi/4)#

#:.tan((19pi)/4)=color(blue)(tan(5pi-pi/4)#

#:.tan((19pi)/4)=color(blue)(-tan(pi/4))=-1#