Menu Close

Show-that-b-R-tan-1-b-tan-1-1-b-pi-2-




Question Number 752 by 112358 last updated on 06/Mar/15
Show that , ∀b∈R^+ ,   tan^(−1) b+tan^(−1) (1/b)=(π/2) .
Showthat,bR+,tan1b+tan11b=π2.
Answered by 123456 last updated on 06/Mar/15
lets f(x):=arctan x+arctan (1/x),x>0  f′(x)=(1/(1+x^2 ))−((1/x^2 )/(1+1/x^2 ))=(1/(1+x^2 ))−(1/(1+x^2 ))=0,x>0  f(x)=c,x>0  f(1)=arctan 1+arctan 1=(π/2)=c  f(x)=(π/2),x>0
letsf(x):=arctanx+arctan1x,x>0f(x)=11+x21/x21+1/x2=11+x211+x2=0,x>0f(x)=c,x>0f(1)=arctan1+arctan1=π2=cf(x)=π2,x>0

Leave a Reply

Your email address will not be published. Required fields are marked *