fx-ESPLUS Series / fx-ES Series
- Q8
- Is there anything I need to keep in mind when performing calculations that involve trigonometric functions or angles?
- A8
Yes. The calculator has three angle modes, and you need to check to make sure that the currently selected angle mode is the correct one for the type of calculation you are trying to perform. If it isn't, you need to change it.
Determining the Current Angle Mode Setting
The current angle mode setting is indicated on the calculator's display by one of the indicators described below.
Degree:
If "D" is on the display, it means that the current angle mode is Degree.
A degree is 1/360 of the circumference of a circle. One degree is represented as 1゜.
The following shows a calculation that uses degrees.
sin90°= cos 0°=1
Radian:
If "R" is on the display, it means that the current angle mode is Radian.
A radian is 1/2πr of the circumference of a circle. Measurement of angles using radians called the "radian system of angular measurement".
1 radian = 360゜/(2π)
The following are calculations that use radians.
sin(π/2) =1 cos (2π)=1
Grad:
If "G" is on the display, it means that the current angle mode is Grad.
A grad is 1/400 of the circumference of a circle.
The following are calculations that use grads.
sin100 grads=cos 400 grads=1
The following shows the relationship between the three angle modes.
90°=π/2 radians=100grads
Degree is the initial default angle mode for a standard scientific calculator.
Changing the Angle Mode
Press [SHIFT] [MODE] key in combination with the number key that corresponds to the angle mode you want to select.