Cos2x 0

What do I solve for cos (2x) = 0? Find all solutions 0

Let's leave 2x for now. How much is cosine?

Let's make an alternative to make it easier to track things for now.

Let's go = 2x

Solve for x for u: x = u / 2

Now your verbal equation becomes:

cos (u) = 0

The domain has also changed.

cos u = 0 if u = pi / 2 + n * pi, where n is a number.

If we leave u = 2x, then zs 2x = pi / 2 + n * pi

Or x = pi / 4 + n * pi / 2 = pi / 4 + n * 2pi / 4

Solve it for n values that are x in spacing [0, 2pi]

n = 0, 1,2,3 (4 solutions)

That cos is 2x pi, so there are 2 complete cycles between 0 and 2pi, i.e. 4 solutions (2 solutions per cycle).

x = ft / 4.3 ft / 4.5 ft / 4.7 ft / 4

Because 2x. Full

Cos2x 0

cos (2x) = 0
This means cos 1 (0) = 2x.
That is, the inverse of 0 is equal to cos 2x.
Now think of these values when the cosine of each Z angle. it is
The cosine of pi / 2 is 0 and the cosine of 3pi / 2 is in the range of 0 to 2pi
There is no other cosine value z !!
Now cos 1 (0) has been replaced with a value.
This means that pi / 2 is equal to 2x, that imp x is equal to pi / 4. is
And because the other has only two values !!!
The idea may be different from your teacher, but we can use any idea to get the answer.
Try to solve cos (x) = 0. I'm thinking of pi / 2 and 3pi / 2.
Then:
2x = pi / 2 and 2x = 3pi / 2
x = pi / 4 and x = 3 pi / 4