Question

The value 5π/24is a solution for the equation 4cos^2(4x)-3=0.
A. True
B. False

Answer 1

\[4\cos ^{2}(4x)-3=0\]\[\cos ^{2}(4x)=3/4\]\[\cos (4x)=\sqrt{3}/2 or
\cos (4x)=-\sqrt{3}/2\]
either 4x=π/6 ----> x=π/24 , x=11π/24
or x = 5π/24 , x=7π/24
answer: A. True