Texas Instruments TI-84 Plus Calculator - Page 8 - Answered Questions & Fixed issues

If you backed up the calculator, you may be able to restore lost data. Failing that, there is nothing you can do.

remove the battery and insert.

The formula to find the volume of right prisms and right cylinders is Volume=(area of base)*height If the cylinder has a circular base, then the area of the base is PI*R^2 and the volume is Pi*(R^2)*H. Here R is measure of the Radius, and H is the measure of the Height. R and H must be expressed in the same unit.

x^2+13x+15=0 Recall (x+a)^2=x^2+2ax+a^2 Write x^2+2*(13/2)x+15, and compare the terms in x. a=13/2 x^2+13x+15=x^2+2(13/2)x+(13/2)^2-(13/2)^2+15 The first three terms are the expansion of (x+13/2)^2 You expression is equivalent to (x+13/2)^2-[(13/2)^2-15]=(x+13/2)^2-[SQRT(109)/2]^2 Use the identity for the difference of two squares a^2-b^2=(a-b)(a+b) This gives x^2+13x+15=(x+13/2)^2-[SQRT(109)/2]^2= [x+13/2 -SQRT(109)/2][x+13/2+SQRT(109)/2] The polynomial can be written as (x-a)(x-b) (Note a has nothing to do with the one used above to complete the square. You can use any name for the roots, x_1, x_2, anything. The two roots are on the screen captures below. PS. I prefer to manipulate exact expressions with radicals. If you do not like it use the decimal approximations.

What are you trying to do on the TI84 Plus. You don't say.

TI calculators have an annoying habit of dimming the screen when the batteries are changed so that it appears as if the calculator isn't turning on. Turn the calculator on (or at least press the ON key). Press and release the 2ND key. Press and hold the Up-arrow key for a few seconds and see whether the screen becomes legible.

Same problem here: - TI 84 Plus is dead (yesterday alive and kicking), - (and exam statistics tomorrow). I removed the 6 torx-screws, and removed the backside (battery-compartment) from the frontside (screen and motherboard). Once the screws are unscrewed, I used my nails to unclip the two parts. What was wrong: Immediately visible was a tiny but fatal corrosion on the two little metal-covered spots on the motherboard, where the metal extensions from the battery-compartment (the backside of TI84) touch the motherboard (frontside). So the power was no longer connected to the + and - entry spots of the motherboard. Solution: I tried to clean the corroded parts, but the thin metal was corroded away, so I bent the two flexible extensions from the battery-compartment a little bit sideways, so they could touch a fresh, non-corroded part of the + and - entry spots on the motherboard. SOLVED!! My Texas Instruments TI84 Plus works again for 100% IMHO this corrosion (Cr metal extension of the battery-compartment, and Cu on the motherboard) can be avoided by using golden contacts like in the rest of the hardware industry. This corrosion problem is a ticking time-bomb, good for sales but not good for our trust in this product ... According to Murphys Law these problems allways occur when you have an important exam the next day ... Hope it helps. Sci4Fixya.

Type: ln(3)/(2ln(3)-ln(5)) See captured image below

There seems to be a limit on the number of trials you can use. The maximum number of trials that I could enter without getting the domain error is 119999. Memory limitations?

Here you are trying to find the intersection point between two curves. Since you could have drawn more than 2 curves, the calculator gives you the opportunity to choose the first curve using the arrow Up/ arrow down to select. Once the curves are chosen, the calculator wants to know where (in the world is Carmen Sandiego) is the intersection point. And no it is not asking you to give the position, just what are the leftmost (1st guess) and rightmost (2nd guess) limits of the interval where the intersection point is. You use the left arrow to go a bit to the left of the intersection point (which you see on the graph) and press ENTER. Then you do the same for the 2nd guess.

The arccosine function is defined for arguments in the range -1 to +1. -125.85/-120.36 is larger than 1 and hence outside the domain of the arccosine function.

TI calculators have an annoying habit of dimming the screen when the batteries are changed so that it appears as if the calculator isn't turning on. Turn the calculator on (or at least press the ON key). Press and release the 2ND key. Press and hold the Up-arrow key for a few seconds and see whether the screen becomes legible.

Well first of all. Dry it a bowl of rice for a few days... (works with every thing hand held). My first guess is that you may have damaged the processor (don't bother trying to replace it). Or (if you can be bothered) open it up and look behind the keypad to see if the keys aren't caught on something. You can NOT return it because warranties don't cover water damage to electronics (normally).

You have several types of graphs Function graphs Y_1=f(x), Y1=3X^2-4, [X, T, Theta, n] key types X Polar graphs r=F(theta), r=r_o*ln(theta). [X, T, Theta, n] types Theta Parametric graphs X_1=f(T) and Y_1=g(T). [X.T, Theta, n] types T Examples: X_1= cos(T). Y_1= 2(1--sin(T)) Sequence graphs u_n+1= f(u_n), [X,T,Theta,n] types n

y-y1=((y2-y1)/(x2-x1))(x-x1) See cap image below

Press APPS. Scroll up or down to reach Inequalz and press ENTER. The inequalz application will know control function graphing. Open the Y= editor to enter at least two inequalities . Use the tabs at the bottom to type in the relational operators. You will have to press [ALPHA] followed by [F1], or [F2], etcPress the GRAPH function key (F5) to draw the graphs. You get the two regions superposed (original shading).Press [ALPHA][F1 or F2] to activate the [SHADES] tab. This open up the following screen.On this screen you can choose the type of shading 1: Intersection of the two regions ( the part of the plane that satisfies both inequalities, 2 the union of the two regions or 3 the original shading (as compared to choice 2). Selecting option 1:intersection gives you the following screen.If you press the [ALPHA][F5] keys you have the HELP ? screen below.If you press the [ALPHA] [F3] keys you get a Point of Interest (You should consult the manual for the Inequalz application for more details.By pressing the TRACE button (not ALPHA F4) and the left or right arrows you you can follow the graph of one of the functions. You jump to the other functions by pressing the Up or Down arrows. To get the manual for Inequalz go to the education.ti.com and download it.

Sorry, the TI-84 only has one font.

keyboard has become faulty...replace it..

See next explanation below

[3(x-5)-4(-3x+2)]-[4(6-x)]
[(3x-15)-(12x+8)]-(24-4x)
(-9x-23)-(24-4x)
-13x-(-1)
this is 9th grade stuff.