Test Index

NCERT Class XI Mathematics - Limits and Derivatives - Solutions

© examsnet.com
Question : 64
Total: 72
sin(x+a)
cosx
Solution:  
Let f (x) =
sin(x+a)
cosx
 ... (i)
Differentiating (i) with respect to x, we get
d
dx
 (f (x)) =
cosx(sin(x+a))′−sin(x+a)(cosx)′
(cosx)2

=
cosxcos(x+a)−sin(x+a)(−sinx)
(cosx)2

=
cosxcos(x+a)+sin(x−a).sinx
(cosx)2

=
cos[x+a−x]
(cosx)2
=
cosa
(cosx)2
© examsnet.com
Go to Question:
Prev Question
Next Question