Solve sin(x)=0, cos(x)=0, tan(x)=0. These are elementary trig. equations.

Explore how images are used to solve trigonometric equations for sin(x), cos(x), and tan(x) at key points on the unit circle. Understand the solutions visually and gain a deeper understanding of these fundamental trigonometric functions.


Trigonometric Equation

\( \sin(x) = 0 \)

Graph of sin(x) = 0

Solutions within \( [0, 2\pi] \):

\( x = 0, \quad x = \pi, \quad x = 2\pi \)

How to interpret the graph:

The graph shows the function \( \sin(x) \) over the interval \( [0, 2\pi] \). The x-axis is marked in terms of \( \pi \). The red dots on the graph represent the points where \( \sin(x) = 0 \). By observing the x-coordinates of these red dots, we can determine the solutions to the equation.


Trigonometric Equation

\( \cos(x) = 0 \)

Graph of cos(x) = 0

Solutions within \( [0, 2\pi] \):

\( x = \frac{\pi}{2}, \quad x = \frac{3\pi}{2} \)

How to interpret the graph:

The graph shows the function \( \cos(x) \) over the interval \( [0, 2\pi] \). The x-axis is marked in terms of \( \pi \). When we say \( \cos(x) = 0 \), it’s akin to saying \( y = 0 \) on a standard coordinate system. This means that for the values of \( x \) where \( \cos(x) \) intersects the x-axis, the y-coordinate is zero. The red dots on the graph represent these points of intersection. By observing the x-coordinates of these red dots, we can determine the solutions to the equation. In this case, the cosine function is zero at \( x = \frac{\pi}{2} \) and \( x = \frac{3\pi}{2} \), which are the points where the graph intersects the x-axis.

Trigonometric Equation

\( \tan(x) = 0 \)

Graph of tan(x) = 0

Solution within \( [-\frac{\pi}{2}, \frac{\pi}{2}] \):

\( x = 0 \)

How to interpret the graph:

The graph shows the function \( \tan(x) \) over the interval \( [-\frac{\pi}{2}, \frac{\pi}{2}] \). The x-axis is marked in terms of \( \pi \). When we say \( \tan(x) = 0 \), it’s akin to saying \( y = 0 \) on a standard coordinate system. This means that for the values of \( x \) where \( \tan(x) \) intersects the x-axis, the y-coordinate is zero. The red dot on the graph represents this point of intersection. By observing the x-coordinate of this red dot, we can determine the solution to the equation. In this case, the tangent function is zero at \( x = 0 \), which is the point where the graph intersects the x-axis.


Trigonometric Equation

\( \tan(x) = 0 \)

Solutions within \( \left[-\frac{\pi}{2}, \frac{\pi}{2}\right] \):

\( x = 0 \)

Explanation:

In the unit circle, the point at \( 0 \) degrees or \( 0 \) radians lies on the x-axis, which means the y-coordinate is \( 0 \). The tangent of \( 0 \) degrees (or \( 0 \) radians) is given by \( \tan(0) = \frac{0}{1} = 0 \). This is why we have \( \tan(x) = 0 \) at \( x = 0 \).

Unit Circle

Refer to the unit circle image above for a visual representation.