ACCORDING TO QUES,
\[f~\left( x \right)\text{ }=\text{ }\surd 3\text{ }sin~x\text{ }~cos~x\text{ }~2ax\text{ }+\text{ }b,\text{ }a~{}^\text{3}\text{ }1\]
differentiating both sides w.r.t. x
WE HAVE
\[f~\left( x \right)\text{ }=\text{ }\surd 3\text{ }cos~x\text{ }+~sin~x\text{ }~2a\]
For increasing function, f’ (x) < 0
HENCE, function is decreasing in R.