Question

( begin{aligned} & sqrt{2+sqrt{2+2 cos .4 theta}} =& sqrt{2+sqrt{2(1+cos 4 theta)}} end{aligned} )
( =sqrt{2+sqrt{4 cos ^{2} 2 theta}}=sqrt{2 times 2 cos ^{2} theta} )
is -ve
in ( pi / 2 ) to ( pi ) ( =sqrt{2+2 cos 2 theta}=2 cos theta )
( =sqrt{2(1+cos 20)} quad B mid frac{operatorname{Am}}{2 m}=-2 cos theta_{1} operatorname{An} Delta )

# Q.13 If <<7, then V2+ 2+2 cos 40 equals (A) 2 cose (B) -2 cose (C) 2 sino (D) –2 sino Q.20

Solution