脪谤诲耻驳丑an sreathach
Tha Gillian a' p脿igheadh c霉mhnant a' f貌n aice mar a chleachdas i e. Tha i airson obrachadh a-mach d猫 na chosg i air teacstan an t-seachdain seo.
Tha aon teacst a' cosg 5sg.
Feumaidh tu cl脿r luachan a dh猫anamh airson suas ri 6 teacstan a' sealltainn na cosgais ann an sgillinnean mar a ch矛 thu gu h-矛osal.
Feumaidh sinn a-nis foirmle a lorg a chuidicheas sinn ag obrachadh a-mach cosgais 脿ireamh sam bith de theacstan.
Bu ch貌ir gum faic thu bhon chl脿r gu h-脿rd gu bheil a' chosgais a' dol suas 5 gach turas.
'S e am foirmle \(C=5\times T\)
Question
Chuir Gillian 87 teacstan air falbh an t-seachdain seo. D猫 chosg Gillian air teacstan an t-seachdain seo?
Cosgais (ann an sgillinnean) = 5 x 脿ireamh theacstan
Gabhaidh seo ath-sgr矛obhadh mar:
\(C = 5 \times T\)
Chuir Gillian 87 teacstan an t-seachdain seo. Faodaidh sinn a-nis am foirmle seo a chleachdadh gus a' chosgais obrachadh a-mach.
\(C = 5 \times T\)
\(C = 5 \times 87\)
\(C = 435sg = \pounds4.35\)
An nmh teirm
Seo 貌rdugh-脿ireamhan a' t貌iseachadh le 1: 1, 4, 7, 10.
Bidh thu a' faighinn na h-ath 脿ireimh le bhith a' cur 3 ris an teirm roimhpe.
Th猫id iarraidh ort gl猫 thric foirmle a lorg airson an nmh teirm.
Question
Lorg an nmh teirm.
Gus seo a dh猫anamh, feumaidh sinn an toiseach an diofar eadar gach teirm a lorg. Innsidh seo p脿irt dhen fhoirmle dhuinn:
\(\text{脪} = 3 \times n\)
Nuair a dh'ionadaicheas sinn \(n = 1\) dhan fhoirmle seo, ch矛 sinn nach obraich e mar \(\text{脪} = 3 \times 1 = 3\), ach 's e 1 a' chiad teirm.
Chan fheum sinn a-nis ach 2 a thoirt-air-falbh.
\(\text{脪} = 3 \times 1 - 2\)
\(\text{脪} = 1\)
Feuch seo a-nis airson theirmean eile gus a bhith cinnteach gu bheil an riaghailt agad ag obrachadh:
Teirm 2
\(\text{脪} = 3 \times 2 - 2\)
\(\text{脪} = 6 - 2\)
\(\text{脪} = 4\,Ceart!\)
Teirm 4
\(\text{脪} = 3x4 -2\)
\(\text{脪} = 12-2\)
\(\text{脪} = 10\,Ceart!\)
Tha am foirmle againn a-nis:
\(\text{脪} = 3 \times n - 2\)
or:
\(\text{脪} = 3n - 2\)
Obraichidh an d貌igh seo daonnan airson 貌rdughan far a bheil an diofar eadar na teirmean a' fuireach mar a bha e.
Question
Lorg an nmh teirm san 貌rdugh 1, 5, 9, 13.
| nmh teirm | 1 | 2 | 3 | 4 | 5 |
| 脪谤诲耻驳丑 | 1 | 5 | 9 | 13 | 17 |
| nmh teirm |
|---|
| 1 |
| 2 |
| 3 |
| 4 |
| 5 |
| 脪谤诲耻驳丑 |
|---|
| 1 |
| 5 |
| 9 |
| 13 |
| 17 |
- An toiseach, lorg an diofar eadar gach teirm
- 'S e 4 an diofar eadar gach teirm
- Leigidh seo leat a' chiad ph脿irt dhen fhoirmle obrachadh a-mach
- T貌isichidh am foirmle airson an 貌rduigh seo le \(\text{脪} = 4n\)
- Thoir s霉il a-nis air gach teirm
- Nuair a tha n = 1, \(\text{脪} = 4 \times 1 = 4\). Ach 's e 1st a' 1d teirm.
- Mar sin feumaidh sinn 3 a thoirt-air-falbh airson a' chiad teirm ceart fhaighinn agus cuideachd d猫anamh cinnteach gu bheil seo ag obrachadh airson an 2ra teirm.
'S e am foirmle airson an 貌rduigh \(\text{脪} = 4n - 3\).