Get Answers to all your Questions

header-bg qa

A function f :R \rightarrow R   stisfies  

\\\sin x \cos y ( f ( 2x + 2y )) - f ( 2x - 2y ) = \ \cos x \sin y ( f ( 2x + 2y )+f ( 2x - 2 y ))

  I\! \! f \: f ' (0) = 1/2 , then :

Option: 1

f''(x ) = f ( x ) = 0


Option: 2

4 f''(x ) + f ( x ) = 0


Option: 3

f''(x ) + f ( x ) = 0


Option: 4

4f''(x ) - f ( x ) = 0


Answers (1)

best_answer

 

Trigonometric functions -

\frac{d}{dx}(sinx)=cosx

\frac{d}{dx}(secx)=secx\:tanx

\frac{d}{dx}(cosec\:f(x))=-cosec\:\left \{ f(x) \right \}\:cot\:\left \{ f(x) \right \}\;f'(x)

-

 

 

\frac{f ( 2x+2y )}{f ( 2x -2y )} = \frac{\sin ( x+ y )}{\sin ( x-y )}

\frac{f \left ( \alpha \right )}{\sin ( \alpha /2 )}= \frac{ f ( \beta)}{\sin \beta /2 }= k

  f(x)=k\sin x/2 

           f^{{}'}(x) = k/2 \cos x/2         f^{''}(x) = -k/4 \sin x/2

           4 f^{''}(x) + f(x) = 0

Posted by

Kuldeep Maurya

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE