Objective:

To use the S and T scales to determine the sine of angles in the range 5.7° to 90° and tangent of angles in the range 5.7° to 45°.

General:

• The S and T scales may appear on the slider or the body of the slide rule depending on the make.
• The S scale ranges from 5.7° to 90°.
• Sine values lie in the range -1 to 1.
• The T scale ranges from 5.7° to 45°.
• Tangent values lie in the range -∞ to +∞.  (Making large values very difficult to read!)
• There are variations in the T scale on some rules.

Method when the S  and T scales are on the Body:

• Move the cursor to the angle on the S scale or the T scale.
• Read the sine or tangent of the angle from the D scale.

Method when the S and T scales are on the Slider:

• Move the cursor to the angle on the S scale or the T scale.
• Read the sine or tangent of the angle from the C scale.

 

The following examples will use the S and T scales on the Slider, a similar process is used if these scales are on the body.
Only the Slider is shown in the diagrams.

Example 1:  Calculate sin30°.

• Move the cursor to S30
• Read the result C0.5

 

Example 2: Calculate sin64.5°.

• Move the cursor to S64.5
• Read the result C0.9

 

Example 3:  Calculate sin 6.2°.

• Move the cursor to S6.2
• Read the result C0.108

 

Example 4:  Calculate tan30°.

• Move the cursor to T30
• Read the result C0.5774

 

Example 5:  Calculate tan44.6°.

• Move the cursor to T44.6
• Read the result C0.986

 

Example 6:  Calculate tan 6.1°.

• Move the cursor to T6.1
• Read the result C0.107

 

Practice Questions:  Calculate the following.

1. sin 14° (Ans:0.242)
2. sin 53° (Ans: 0.8)
3. tan 25.5° (Ans: 0.477)
4. tan 40° (Ans: 0.839)