Casio Fx82tl Manual

							36  Mastering the Calculator using the Casio fx-82TL
Example 1
Solve equation 
Taking logs of both sides;
To find the value of a, the keystrokes are:
The display should read 4.3219281.
So, . Confirm this by using the  key.
Example 2
Given , find the value of y
The  key is above the log key. Hence the keystrokes are:
The display should read 38.370725
Example 3 (harder)
Given , find the value of x
To  f i n d  l o g  x, the calculator keystrokes are:
The display should read 0.5187675.
2a20=
log 2 log 20
log 2 log 20
log 20
log 2
a
a
a=
⇒=
⇒=
4.32220≈yx
log y1.584 =
log y1.584 =
 
y ⇒101.584=
10x
logx 61.5=
log 6 1.5
log 61.5log
log 6
log1.5
x
x
x
=
⇒=
⇒= 
						

							Mastering the Calculator using the Casio fx-82TL  37
Since this is the value of log x, you still need to find x where 
Without removing the answer of 0.5187675 on your display, press:
Your display should now read 3.3019272
Note: You could use the ‘ln’ key instead of the ‘log’ key – the answer would still be the same. 
Try it!
14. Degrees, minutes, seconds
The key involved is 
This key can be used for problems involving degrees, minutes and seconds or hours, minutes 
and seconds. 
0.518767510 x= 
						

							38  Mastering the Calculator using the Casio fx-82TL
Example 1
Suppose that you have a trigonometric problem where the angle involved is given in degrees 
and minutes. e.g. Find x where 
’
The keystrokes involved are:
The display should show 1.728343, so x is approximately 1.73
Example 2
If you wish to convert an angle in degrees to its equivalent in degrees, minutes and seconds:
e.g. 34.88°, the keystrokes are:
The display should read 34°52°48
Example 3
To find the sum of 5 hours 52 minutes 30 seconds and 7 hours 45 minutes 49 seconds:
The keystrokes are:
The display should read 13°38°19 which is 13 hours 38 minutes and 19 seconds.
To convert this number on the display into hours and the decimal part of an hour, press
The display should read 13.638611 (hours).
x4sin25° 36×= 
						

							Mastering the Calculator using the Casio fx-82TL  39
Review calculator exercises
1. Perform the following calculations
(i) (5 + 4) × 3
(ii) 12.5 – 8 ÷ 0.5
(iii)
(iv)
(v)
(vi)
(vii)
(viii)
(ix)
(x)
(xi)
2. The following data is on growth (in $m) in an economy over a 8 year period:
2.5 6.2 -2.1 0.04 8.2 7.4 2.1 -1.7
Calculate (i) Σx(ii) Σx2(iii) (Σx)2 Explain in words what each of these mean.
368–×
4---------------------
12.8
1
6.5 3.8–------------------------
70.4117+×
47+ ()2 ×--------------------------------
2.4
3
4 -- - -
------
145.6 17.225⁄ –
345.6 17.22–5⁄
25327×
1.02 3
0---------------------+
4.1333 3.000– ()2.0150.1366
2
6 -------------------0.2000
2
6 -------------------+ ±
100 90– ()2
90----------------------------50 60– ()
2
60 -------------------------20 30– ()
2
30 -------------------------++ 
						

							40  Mastering the Calculator using the Casio fx-82TL
Calculator solutions
1.
(i) (5 + 4) × 3= 27
Make sure your calculation is in comp mode.
(ii) 12.5 – 8 ÷ 0.5 = -3.5
(iii)= 2.5
Either (3 × 6 – 8) ÷ 4 =, or 3 × 6 – 8 = ÷ 4 =
(iv)= 1.007874
Either 12.8 ÷ (16.5 – 3.8) =, or 16.5 – 3.8 = x-1 × 12.8 =
(v)= 0.9
Either ... ÷ ((4 + 7) × 2) = or ... ÷ (4 + 7) ÷ 2 =
(vi)= 3.2
Either 2.4 ÷ (3 ÷ 4) =, or 2.4 ÷ 3 ab/c 4 = 
(vii)= 9.296..
Either 145.6 – 17.2x2 ÷ 5 = √ =, or √ (145.6 – 17.2x2 ÷ 5) =
(viii)= 1.41..
Either 345.6 – 17.2x2 = √ = ÷ 5 =, or (345.6 – 17.2x2) = √ = ÷ 5
(ix)= 39.4985
25 + 3 × 27 ÷ 1.02 ÷ √ 30 
(x)= 1.3325 or 0.9341
Calculator keys: 0.1366 x2 ÷ 6 + .2 x2 ÷ 6 = √ = x 2.015 = M+
+ 4.1333 – 3 
= AC 4.1333 – 3 – RCL M+ =
368–×
4---------------------
12.8
1
6.5 3.8–------------------------
70.417+×
47+ ()
2×-----------------------------
2.4
3
4 -- - -
------
145.6 17.225⁄ –
345.6 17.22–5⁄
25327×
1.02 3
0---------------------+
4.1333 3.000– ()2.0150.1366
2
6 -------------------0.2000
2
6 -------------------+ ± 
						

							Mastering the Calculator using the Casio fx-82TL  41
(xi)= 6.1111
Calculator keys: (100 – 90) x2 ÷ 90 + (50 – 60) x2 ÷ 60 + (20 – 30) x2 ÷ 30 =
2. The following data is on growth (in $m) in an economy over a 8 year period:
2.5 6.2 -2.1 0.04 8.2 7.4 2.1 -1.7
Calculate (i) Σx(ii) Σx2(iii) (Σx)2 Explain in words what each of these mean.
To do this on the calculator, you must be in SD mode. Enter the data:
mode 2 2.5  M+  6.2  M+  2.1  (–)  M+  .04  M+  8.2  M+  7.4  M+  2.1  M+  1.7  (–)  M+
(i) 22.64 Press the key that says Σx ()
This gives the total growth over the last 8 years
(ii) 178.4016 Press the key that says Σx2 () This gives the sum of 
the squares of the growth in each year
(iii) 512.5696 Press Σx and x2. This gives the square of the sum of the growth.
100 90– ()2
90----------------------------50 60– ()
2
60 -------------------------20 30– ()
2
30 -------------------------++