How can I solve this questions and get those answers????

answers
sec 13pi/4=? =>-�ã(2)
csc 13pi/4=? =>-�ã(2)
sec (-pi/6)=? =>2�ã(3)/3

13/4 = 3 1/4 = 2 + 1 1/4

so twice around + pi + pi/4
which is
45 degrees below -x axis
cos 5 pi/4 = -1/sqrt 2 so sec 5 pi/4 = -sqrt 2

the others are similar
Just remember once all the way around is 2 pi and halfway around is pi

To solve the given trigonometric questions and find their answers, you can use the unit circle and the trigonometric definitions of the functions involved. Here's the step-by-step process:

1. sec 13pi/4:
- Convert the angle to radians: 13pi/4 = 3.25pi
- Locate the angle 3.25pi on the unit circle. As secant is the reciprocal of cosine, you need to find the cosine value.
- At 3.25pi, the unit circle intersects the x-axis at (-1, 0), so the cosine value is -1.
- Take the reciprocal of the cosine value: sec 13pi/4 = 1/-1 = -1.

2. csc 13pi/4:
- Convert the angle to radians: 13pi/4 = 3.25pi
- Locate the angle 3.25pi on the unit circle. As cosecant is the reciprocal of sine, you need to find the sine value.
- At 3.25pi, the unit circle intersects the y-axis at (0, -1), so the sine value is -1.
- Take the reciprocal of the sine value: csc 13pi/4 = 1/-1 = -1.

3. sec (-pi/6):
- Convert the angle to radians: -pi/6.
- Locate the angle -pi/6 on the unit circle. As secant is the reciprocal of cosine, you need to find the cosine value.
- At -pi/6, the unit circle intersects the x-axis at (√3/2, 1/2), so the cosine value is √3/2.
- Take the reciprocal of the cosine value: sec (-pi/6) = 1/(√3/2) = 2√3/3.

Hence, the answers are:
- sec 13pi/4 = -1
- csc 13pi/4 = -1
- sec (-pi/6) = 2√3/3.