Question #9ab7b

1 Answer
Dec 18, 2017

Let's see.

Explanation:

Given,

cosacosb-sinasinb=1

:.color(red)(cos(a+b)=1))

:.sin(a+b)=0

:.color(red)(sinacosb+cosasinb=0)......(1).

Now given rarr

color(red)(1+cotatanb)

=1+(cosasinb)/(sinacosb)

=(sinacosb+cosasinb)/(sinacosb)

=color(red)(0)........From (1).

Hence Proved.

Hope it Helps:)