Wednesday, July 23, 2014

Solve for x on the interval [0, 2pi]: 4cos(2x)sin(2x)=1

4*cos(2x)*sin(2x) = 1


First
we will divide by 2 .


==> 2cos(2x)*sin(2x) =
1/2................(1)


Now we will use trigonometric
identities to solve.


We know that: sin2x =
2sinx*cosx


==> sin4x =
2sin(2x)*cos(2x)


Then we will substitute into
(1).


==> sin(4x) =
1/2


But we know that if sin(a)= 1/2 ==> a = pi/6 ,
and  5pi/6.


==> 4x = pi/6 ==> x =
pi/24


==> 4x = 5pi/6 ==> x =
5pi/24


Then the answer is:  x= { pi/24,
5pi/24}

No comments:

Post a Comment

Can (sec x - cosec x) / (tan x - cot x) be simplified further?

Given the expression ( sec x - csec x ) / (tan x - cot x) We need to simplify. We will use trigonometric identities ...