CmpFreak88 Posted August 29, 2006 Alright so I've got my TI-89 and I'm working through my first homework assignment with it, woohoo! And I get to a 3,4,5 right triangle, so I try and use the calculator to solve one of the angles, so I go ahead and input cos^-1(3/5) and then it just spits the same thing back out at me! So I try it with just cos(3/5) and it does the same! Same with tan and sin! Now... I now this calculator does everything, but how do I do this? I think what I'm going to have to do is input approx(cos^-1(3/5)) in order to get my answer? That's kinda lame if you ask me... Quote Share this post Link to post Share on other sites
lilkev715 Posted August 29, 2006 (edited) You have to set your calculator to Degree mode first, it is set to Radian mode by default. Or you can convert radians to degrees, or vice versa. radians--> degrees: (180)/(pie)(radians) degrees--> radians: (pie)(radians)/(180) Hope this helps you out. Edited August 29, 2006 by lilkev715 Quote Share this post Link to post Share on other sites
martymcfly Posted August 29, 2006 What level math is this? Quote Share this post Link to post Share on other sites
lilkev715 Posted August 29, 2006 Looks like basic Trig to me. Quote Share this post Link to post Share on other sites
CmpFreak88 Posted August 29, 2006 Yeah changed all the modes and such, I just had to use approx(cos(3/5)) and that gave me the angle. Oh and this is for Calculus, we're doing our review. Quote Share this post Link to post Share on other sites
martymcfly Posted August 29, 2006 (edited) Go into "Mode" and change "Exact" to "Approx". Edited August 29, 2006 by martymcfly Quote Share this post Link to post Share on other sites
94Camaro Posted August 29, 2006 Go ahead and enter it just like you were, but instead of pressing enter, press the green diamond key, and then press enter. I find it easier to leave the exact/approx setting on auto and just press that one extra key when I need the approx, cause I need the exact quite a bit as well. Quote Share this post Link to post Share on other sites
DECwakeboarder Posted August 29, 2006 Personally I leave mine on exact and then use the diamond key+enter for when I need an approx value...teachers love it when you give them a perfect, exact value every time (until they realize the power of the 89 and make you use a 83 ) Quote Share this post Link to post Share on other sites
LoArmistead Posted August 29, 2006 I was asked (while taking an upper level calc course) what I thought the single greatest invention by man was. I responded with, "The TI-89." Without that beautifully crafted piece of American ingenuity, I would have jumped out of a third floor window multiple times by now. I always thought the 83 was God's gift to man, but when I discovered the capabilities of the 89, I was in awe. ...and yes I believe diamond + enter should convert it to longhand. I remember experiencing that with roots. Quote Share this post Link to post Share on other sites
ic3_man Posted August 29, 2006 I was asked (while taking an upper level calc course) what I thought the single greatest invention by man was. I responded with, "The TI-89." Without that beautifully crafted piece of American ingenuity, I would have jumped out of a third floor window multiple times by now. I always thought the 83 was God's gift to man, but when I discovered the capabilities of the 89, I was in awe. ...and yes I believe diamond + enter should convert it to longhand. I remember experiencing that with roots. You guys got to use a calculator in class for calc? We never got even touch one at all, everything had to be done using your brain and a pencil... Quote Share this post Link to post Share on other sites
hardnrg Posted August 29, 2006 oh come on now... how do you do arccos(3/5) in your head, or even on paper? do you use slide rule? or draw it out and use a protractor?! oh wait... i know... a cosine/sine/tangent lookup table!!!! rofl!!! i've seen those! Quote Share this post Link to post Share on other sites
