Solve the equations below exactly. Give your answers in radians, and find all possible values for t in the interval 0≤t≤2π. If there is more than one answer, enter your solutions in a comma separated list.

(a) sin(t)=2/√2 when t=


(b) cos(t)=1/2 when t=


(c) tan(t)=−1 when t=

User Icon for Steve Steve answered
7 years ago

you should review your basic standard triangles:

45-45-90: sides 1:1:√2
30-60-90: sides 1:√3:2

Each problem here will have two solutions, in the quadrants where the named function is positive or negative.

User Icon for Explain Bot Explain Bot answered
11 months ago

To solve these equations exactly and find all possible values for t in the interval 0≤t≤2π, we will use the unit circle and trigonometric properties.

(a) sin(t) = 2/√2
To find the exact value of t, we first need to determine the reference angle by taking the inverse sin of 2/√2.
sin^(-1)(2/√2) = π/4

Next, we need to identify the quadrants where sin is positive. Since the given sin(t) = 2/√2 is positive, t must lie in the first and second quadrants.

In the first quadrant (0 ≤ t ≤ π/2), the reference angle is π/4. So, one possible value for t is π/4.

In the second quadrant (π/2 ≤ t ≤ π), the reference angle is also π/4. However, the angle is measured in the clockwise direction. So, the second possible value for t is 3π/4.

Therefore, the solutions for (a) are t = π/4, 3π/4.

(b) cos(t) = 1/2
Similar to part (a), we will start by finding the reference angle by taking the inverse cos of 1/2.
cos^(-1)(1/2) = π/3

Next, we need to identify the quadrants where cos is positive. Since the given cos(t) = 1/2 is positive, t must lie in the first and fourth quadrants.

In the first quadrant (0 ≤ t ≤ π/2), the reference angle is π/3. Therefore, one possible value for t is π/3.

In the fourth quadrant (3π/2 ≤ t ≤ 2π), the reference angle is also π/3. However, the angle is measured in the clockwise direction. So, the second possible value for t is 5π/3.

Therefore, the solutions for (b) are t = π/3, 5π/3.

(c) tan(t) = -1
To find the exact value of t, we will take the inverse tangent of -1.
tan^(-1)(-1) = -π/4

Next, we need to identify the quadrants where tan is negative. Since the given tan(t) = -1 is negative, t must lie in the second and fourth quadrants.

In the second quadrant (π/2 ≤ t ≤ π), the reference angle is π/4. Therefore, one possible value for t is 3π/4.

In the fourth quadrant (3π/2 ≤ t ≤ 2π), the reference angle is also π/4. However, the angle is measured in the clockwise direction. So, the second possible value for t is 7π/4.

Therefore, the solutions for (c) are t = 3π/4, 7π/4.

To summarize:
(a) The solutions are t = π/4, 3π/4.
(b) The solutions are t = π/3, 5π/3.
(c) The solutions are t = 3π/4, 7π/4.

Remember, when dealing with angles, there are infinite solutions due to the periodicity of trigonometric functions. The solutions provided are within the specified interval 0 ≤ t ≤ 2π.