NIMCET 2014 Question Paper with solutions

Question : 39 of 120

Marks: +1, -0

If tan A - tan B - x and cot B - cot A = y, then cot (A - B) is equal to

Solution:

We have,
tan A - tan B = x ... (i)
and cot B - cot A = y ... (ii)
Then , cot (A - B) =

{cotAcotB}/{cotB-cotA}

{1+cotAcotB}/y

... (iii)
From Eq. 1

1/{cotA}-1/{cotB}

= x
⇒

{cotB-cotA}/{cotAcotB}

= x
⇒ cot A cot B =

y/x

From Eq. (iii).
cot (A - B) =

{1+y/x}/y

1/x+1/y

Go to Question:

Prev Question

Next Question