Question #75f9a

1 Answer
Nov 23, 2016

Given tan(alpha-beta)=7/24 and tanalpha=4/3

So (tanalpha-tanbeta)/(1+tanalphatanbeta)=7/24

=>(4/3-tanbeta)/(1+4/3tanbeta)=7/24

=>32-24tanbeta=7+28/3tanbeta

=>100/3tanbeta=25

=>tanbeta=3/4

So cotalpha =3/4 and cotbeta=4/3

Now

cot(alpha+beta)=(cotalphacotbeta-1)/(cotbeta+cotalpha)

=>cot(alpha+beta)=(3/4xx4/3-1)/(4/3+3/4)=0=cot(pi/2)

=>alpha+beta=pi/2

proved