Texas Instruments 30Xa Calculator

Transcription

1 Teas Instruments 30Xa Calculator Keystrokes for the TI-30Xa are shown for a few topcs n whch keystrokes are unque. Start by readng the Quk Start secton. Then, before begnnng a specfc unt of the tet, check to see f ths ncludes keystrokes for that unt. Gong through the keystrokes before class wll help, especally f your nstructor cannot nclude nstructons for the TI-30Xa durng class. Quk Start Calculator regsters. Most keys have 2 functons. One appears n whte on the face of the key. The second functon appears n gold above the key. To access the functon appearng n gold, press [2nd] frst. Arthmetc. Arthmetc can be done as shown below. Eample: Multply,222 by 32.8,222 [ ] 32.8 [ = ] 40,08.60 answer Notce, when keyng n,222 we dd not key n a comma (there s no comma key). The comma s shown n keystrokes for clarty. Also, notce that we dd not key n the decmal pont when enterng,222; the calculator presumes there s a decmal pont at the far rght. Correctng entres. To erase the last dgt entered, press [ ² ]. Pressng [ON/C] durng an operaton clears that operaton. Pressng [ON/C] after an operaton s complete clears the dsplay. Negatve numbers. The sgn of a dsplayed number can be changed by pressng [+ W -]. nd Settng the decmal. To change the decmal settng, press [2 ] [FIX], then type the number of decmal places you want nd (from 0 to 9). For a floatng decmal, press [2 ] [FIX] [. ]. Tme-savng regsters. Suppose we want to calculate the total monthly rent on a 72-unt apartment buldng n whch 36 unts rent for $850 each, 24 rent for $900 each, and 2 rent for $925 each. One approach would be to wrte down subtotals, then add subtotals: Here are two other approaches: 36 $850 $30, $900 2,600 2 $925 +,00 Total $63,300 use storage regsters 36 [ ] 850 [ = ] 30, frst subtotal [STO] 30, stored n regster 24 [ ] 900 [ = ] 2, second subtotal [STO] 2 2, stored n regster 2 2 [ ] 925 [ = ],00.00 thrd subtotal [ + ] [RCL] 30, frst subtotal, recalled [ = ] 4, result [ + ] [RCL] 2 2, second subtotal, recalled [ = ] 63, total use parentheses 36 [ ] 850 [ = ] 30, frst subtotal [ + ] ( 24 [ ] 900 ) 2, second subtotal [ + ] ( 2 [ ] 925 ),00.00 thrd subtotal [ = ] 63, total

2 Unt 3. Mathematcal symbols and epressons 2 5 Eample 2 Use a calculator to fnd the value of: a. 23 b [ ] result 4 [ y ] 5 [ = ] result Unt 4.2 The percent formulas Eample (Arthmetc porton) Multply 5,600 by 70%. multply by a decmal number 5,600 [ ].70 [ = ] 3, answer multply by a percent 5,600 [ ] 70 [2nd] [ % ] [ = ] 3, answer Unt 4.3 Increase and decrease problems Eample You buy a TV for $350. You must also pay sales ta of 6%. Frst fnd the amount of sales ta. Then, determne the total amount you must pay prce of TV [ + ] 6 [2nd] [ % ] 2.00 sales ta [ = ] total amount due Eample 3 You retan a real estate agent to help sell your home. The home sells for $200,000, and you have agreed to pay your real estate agent a 7% commsson. Frst fnd the commsson. Then, determne the net amount you wll receve after the commsson. 200, ,000 sellng prce [ - ] 7 [2nd] [ % ] 4, commsson [ = ] 86, net, after the commsson Chapters 0 & Compound nterest formulas Usng a calculator properly s essental n workng wth the compound nterest formulas of Illustraton 0-. An eample wll be gven for each of the 8 compound nterest formulas. We wll begn wth Formula A. Before startng, here are a few thngs worth notng: C There are several ways to do the arthmetc; the keystrokes shown n ths secton are only one choce. The keystrokes shown may, n some cases, be longer than another method but are used because the method s consdered to be more conceptually sound and easer to remember. C Here s a tp: Try your own keystrokes before lookng at ours. If your approach makes sense, use t because t wll be easer to remember. If you have dffculty, then revew our suggested keystrokes. C The dsplayed values shown n the keystrokes have 2 decmal places. Havng our decmal set at more or less places wll not affect the fnal answer, provded we use chan calculatons (remember that chan calculatons use the nternal, more accurate value, not the dsplayed value).

3 Formula A Eample of Unt 0.2 You get an ncome ta refund of $,700 and depost the money n a savngs plan for 6 years, earnng 6% compounded quarterly. Fnd the endng balance usng compound nterest formulas. n 24 FV = PV ( + ) = $,700 (.05) = $2, [ y ] 24 [ = ] to the 24th power [ ],700 [ = ] 2,430.5 answer Eample 2 of Unt 0.2 Suppose a wse man had deposted $ n a savngs account 2,000 years ago and the account earned nterest at 2% compounded annually. If the money n the account today were evenly dvded among the world s populaton, how much would each person receve, based on a world populaton of 7 bllon? n 2000 FV = PV ( + ) = $ (.02) Then dvde by 7,000,000, [ y ] 2,000 [ = ].59 7 account balance, n scentfc notaton [2nd] [FIX] balance, wth more dgts, scentfc notaton [ ] 7,000,000,000 [ = ] 22,659, amount per person [2nd] [FIX] 2 22,659, decmal back to 2 places Formula B Eample 4, Unt 0.2 You depost $00 at the end of each year for 4 years, earnng 6% compounded annually. Use compound nterest formulas to fnd the balance n 4 years. FV ' PMT ( % )n & $00 (.06)4 & = = $ [ y ] 4 [ = ] [ - ] [ = ] 0.26 value of numerator [ ].06 [ = ] 4.37 value nsde of brackets [ ] 00 [ = ] FV Formula 2A Eample of Unt 0.3 Your aunt says she wll gve you $2,430.5 n 6 years. Assumng that you can earn 6% compounded quarterly, what s the real value of her promse, n today s dollars? PV ' FV ( % ) ' $2,430.5 n (.05) 24 = $, [ y ] 24 [ = ].43 value of denomnator [STO].43 ths value s stored n regster 2,430.5 [ ] [RCL].43 recalled the value [ = ], answer

4 Formula 2B Eample 2 of Unt 0.3 You are sellng a valuable con. You have two offers. The frst offer s for $5,500 cash. Wth the second offer, the buyer wll pay you $2,000 at the end of each year for 3 years. Assumng that you can earn 8% compounded annually on your money, whch offer s better? PV ' PMT & ( % ) n & (.08) = $2,000 3 = $5, [ y ] 3 [ = ] to the thrd power [/] 0.79 over (.08 to the thrd power) [+ W -] changed the sgn [ + ] [ = ] 0.2 value of the numerator [ ].08 [ = ] 2.58 value nsde the brackets [ ] 2,000 [ = ] 5,54.9 answer Formula 3 Eample of Unt.4 Dale bought a rare baseball card 3 years ago for $,500. He just sold the card for $2,000 to get some money for hs college tuton. What nterest rate, compounded annually, dd Dale earn on the nvestment? ' FV PV n & $2,000 = 3 & = % (wth 4 decmal places) $,500 2,000 [ ],500 [ = ].33 value nsde of parentheses [ y ] ( [ ] 3 ) [ = ].0 prevous value to the /3 power [ - ] [ = ] 0.0 rate, n decmal form, wth decmal at 2 [2nd] [FIX] rate, n decmal form, wth decmal at 6 [2nd] [FIX] put decmal back at 2 places Formula 4A Eample 2 of Unt. You want to accumulate $200,000 for retrement n 40 years. You can earn 6.75% compounded monthly. What amount must you depost at the end of each month n order to accumulate $200,000 n 40 years? PMT ' FV () ( % ) n & = $200,000 ( ) = $8.7 ( ) 480 & [ y ] 480 [ = ] [ - ] [ = ] 3.77 value of denomnator [STO] 3.77 stored the value 200,000 [ ] [ = ],25.00 value of numerator [ ] [RCL] 3.77 denomnator, recalled [ = ] 8.7 answer

5 Formula 4B Eample 2 of Unt.2 Suppose you have accumulated $500,000, perhaps from many years of savngs or from an nhertance. You put the money n a savngs plan earnng 6% compounded monthly. You want the plan to last 40 years. How much can you wthdraw at the end of each month? PMT ' PV () & ( % ) n $500,000 (.005) = = $2,75.07 & (.005) [ y ] 480 [ = ] 0.96 th.005 to the 480 power [/] 0.09 th over (.005 to the 480 power) [+ W -] changed the sgn [ + ] [ = ] 0.9 value of denomnator [STO] 0.9 stored the value 500,000 [ ].005 [ = ] 2, value of numerator [ ] [RCL] 0.9 recalled the denomnator [ = ] 2,75.07 answer

6 Formula 5 Eample 3 of Unt. You want to start a restaurant busness and estmate t wll take $28,000 to get started. You currently have $3,000 and can depost an addtonal $425 at the end of each month. If your savngs wll earn 9% compounded monthly, n how many months can you start your busness? For Formula 5 we must use proper sgn conventon for PV, FV, and PMT: PV = negatve $3,000 (negatve because you pay ths amount nto a savngs plan) FV = $28,000 (postve because you wll get ths amount back from the savngs plan) PMT = negatve $425 (negatve because you pay ths amount nto a savngs plan) n ' &ln PV % ( PMT ) PMT & FV ln(%) &$3,000 % &$ &ln &$ & $28,000 = = months ln(.0075) Step : Compute and store (-$425 over.0075) 425 [+ W - ] [ ].0075 [ = ] -56, value of ( - $425 over.0075) [STO] -56, stored n regster Step 2: Compute and store the value of the denomnator nsde of large brackets [ - ] 28,000 [ = ] -84, value of the denomnator nsde of large brackets [STO] 2-84, stored n regster 2 Step 3: Compute and store the value of the man denomnator.0075 [LN] 0.0 the natural log of.0075 [STO] stored n regster 3 Step 4: Compute the value of total numerator [RCL] -56, value of ( - $425 over.0075) [ - ] 3,000 [ = ] -59, value of numerator nsde of large brackets [ ] [RCL] 2-84, denomnator nsde of large brackets, recalled [ = ] 0.70 total value nsde of large brackets [LN] the natural log of the prevous value [+ W - ] 0.35 value of the total numerator Step 5: Fnd answer [ ] [RCL] recalled [ = ] answer Formula 5 47