A) \[a\in (-5,5)\]
B) \[a\in (-\infty ,-5)\]
C) \[a\in (0,+\infty )\]
D) None of these
Correct Answer: B
Solution :
[b] \[f'(x)=a+3\cos x+4\sin x\] \[f(x)\] is one-one if \[f'(x)>0\] for all x or \[f'(x)<0\]for all x. So, \[f'(x)<0\forall x,\] if \[a<-5\] and \[f'(x)>0\forall x,\] if \[a>5\] \[\therefore \,\,\,a\in (-\infty ,-5)\cup (5,\infty )\]
You need to login to perform this action.
You will be redirected in
3 sec
