I have to take the secant of -1.2. I'm supposed to get a degree. I can't figure out the order to push buttons. PLEASE help!
TWO THINGS YOU NEED TO KNOW, Eli.
1. Secant will NEVER return a degree measure (or even a radian measure) no matter what computer or calculator you use. The reason is because secant returns the ratio of sides (hypotenuse over adjacent), which has a range of [1, infinity). So, to put this in basic math terms: all six trig functions have ANGLE INPUTS (degrees & radians) while spitting out SIDE-RATIO OUTPUTS (for instance, the height of the tree in relation to the distance away from it).
2. DEGREE MODE: All the TI calculators I've ever used have a way to switch between RADIAN mode & DEGREE mode. If you're taking pre-calc or trigonometry I'd suggest staying in degree mode; if you're taking Calculus or more advanced mathematics then I'd seriously suggest sticking with radian mode. Either way, go to your MODE screen and toggle it to the desired setting. ALSO, if you're graphing a trig function then you will want to be in radian mode.
Now...to try to answer your question:
A. You are either asking to find the ARCSECANT of -1.2.
B. You are asking to find the SECANT of -1.2 radians.
A. TI-84 does not have a SECANT button (from what I remember); because the reciprocal trig functions aren't as important as sine, cosine, and tangent. This isn't bad news. All you need to do to find the arcsecant (aka the inverse secant) of a value is find the arccosine of that value [arccos(-1.2)] and find its reciprocal (ie, flip the number upside down: the reciprocal of 5 is one-fifth). Viola, you're done.
B. TI-84 only uses the three basic trig functions. Secant is the reciprocal of cosine. Therefore, in order to find the secant of -1.2 radians you need to be in Radian mode (see #2 above). From there, you just find the cosine of -1.2 and take that values reciprocal (ie, flip the number upside down: the reciprocal of 10 is point one) . Viola, you're done.
Math lesson: 1 Radian = 180 Degrees. Therefore, 1.2 Radians is roughly one-third of pi, therefore it is roughly one-third of 180 degrees; therefore -1.2 radians would be nearly -60 degrees (a very friendly angle measure).
I hope that helps If not, you should call Texas Instruments because they've got friendly people who are happy to assist anyone. Questions like this are right up their ally, advanced questions like the syntax of the poisson cumulative distribution function are not. So, you're fine. For in depth math help holler at www.THEMATHCHEETAH.com
In Short: Secant returns ratios and NOT degrees or radians. Secant is the reciprocal to cosine. Arcsecant WILL return degrees/radians. Your calculator can be set to either mode.
TEXAS INSTRUMENTS >>>>> all calculators ever made.
Mar 08, 2011 |
Texas Instruments TI-84 Plus Calculator