Math 140
2.3: Computing the Six Trigonometric Functions on your Calculator
Trigonometry
What Keys to Use
For sine, cosine, and tangent use the SIN , COS, and TAN keys.
There are no keys for cosecant, secant, and cotangent. The only way to get these functions is to understand that
csc θ =
1
sin θ
sec θ =
1
cos θ
cot θ =
1
tan θ
so, if you need cosecant you need to hit 1 ÷ SIN
Radian Mode and Degree Mode
You need to specify to your calculator whether the numerical data that you enter will be in radians or degrees.
The easiest way to do this is to highlight the correct entry on the MODE menu.
For radian mode use:
For degree mode use:
If you want another way to do this without changing modes all the time, then just keep your calculator
ALWAYS in RADIAN mode (since this is most common) and if you need to enter something in degrees then
use the degree key 1: ° under the ANGLE menu.
Put calculator in RADIAN mode, then try …
sec 57°
cos
π
12
cot
π
8