Question

$\sqrt{2 + \sqrt{2 + 2 \cos(4x) } }$
under 2 + under root 2 + cos 4 theta under root 2 + under root 2 + 2 cos 4 theta

Answer 1

hey dear !

√(2+√(2+2cos4x))

=) √(2+√2(1+cos4x))

we know that : 1+cos@ = 2cos^2@/2

apply above formula we get ,

=)√(2+√2.2cos^2(2x))

=) √(2+√4cos^2(2x))

=) √(2+2cos(2x))

=) √2(1+cos(2x))

=) √2.2cos^(2x/2)

=)√4cos^2(x)

=) 2cos(x)

#shreya