Q18 of 285 Page 409

Find , when:
tan (x + y) + tan (x — y) = 1

Let us differentiate the whole equation w.r.t x

Formula :

Therefore ,

Find , when:

e^x log y = sin^—1 x + sin ^—1y

Find , when:

xy log (x + y) = 1

Find , when:

If y = x sin y , prove that .

There is correction in question …. Prove that should be
instead of to get the required answer.

Find , when:tan (x + y) + tan (x — y) = 1