Question

If cot theta = 5/9 ,
the value of
((1 + cos theta)(1 - cos theta))
/
((1 - sin theta)(1 + sin theta)) is :
​

Answer 1

Answer:

81 / 25 is the answer to the given question

Answer 2

Answer:

81/25

cottheta=coso/sino=5/9

it can be rewritten as sino/coso=9/5

from the question

(1+coso)(1-coso)

-----------------------

(1-sino)(1+sino). using (a+b)(a-b)=a^2-b^2

the above expression rewritten as

1-cos^2theta

–-----------------------

1-sin^2theta

sin2 theta

---------------

cos^2theta. (sin^2theta+cos^2theta =1)

sin^2theta=1-cos^2theta

cos^2theta=1-sin^2theta

(9/5)^2

81/25 is the answer