(6) Csc of Angle XAB:

csc XAB = -csc X1AB = -csc (XAB - 180)

i. The functions of any angle between 270 and 360€ may be expressed as the function of the

acute angle, which is found by subtracting the given angle from 360€. Assuming that angle XAB in

Figure 4-15, page 22, can have any value from 270€ to 360€, you can derive the following formulas for

the functions of any angle in the fourth quadrant.

(1) Sin of angle XAB:

sin XAB = -sin (360 - XAB)

(2) Cos of angle XAB:

cos XAB = cos (360 - XAB)

(3) Tan of angle XAB:

tan XAB = -tan (360€ - XAB)

(4) Cot of angle XAB:

cot XAB = -cot (360€ - XAB)

(5) Sec of angle XAB:

sec XAB = sec (360 - XAB)

(6) Csc of angle XAB:

csc XAB = -csc (360€ - XAB)

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