Use substitution to determine whether the given xvalue is a

Use substitution to determine whether the given x-value is a solution of the equation. cos x = sin 3x, x = pi/3 x = pi/3 is not a solution of the equation. x = pi/3 is a solution of the equation.

Solution

cos x = sin 3x

plugging x = pi/3 in the equation

cos pi/3 = sin 3( pi/3 )

cos pi/3 = sin pi

plugging the values of cos pi/3 and sin pi

1/2 is not equal to 0

hence x = pi/3 is not a solution