Arithmetic Progression (AP) — ক্লাস ১০
হেল্ল’ বন্ধু! 😊 আজিৰ পাঠত আমি শিকিম Arithmetic Progression (AP) step by step। Math আনন্দদায়ক আৰু playful হ’ব, কাৰণ আমরা যোগ কৰিম কিছু jokes আৰু fun facts।
শিক্ষা যেন এটা যাত্ৰা, আৰু প্ৰতিটো পদক্ষেপেই মূল্যবান।
দয়া কৰি 1–2 সপ্তাহৰ ভিতৰত পুনৰ পৰিদৰ্শন কৰক, নতুন আনন্দৰ বাবে! 📚✨
সূচী
সংজ্ঞা
Arithmetic Progression (AP) হৈছে সংখ্যাৰ এটা series, য’ত প্ৰতিটো সংখ্যা আগৰ সংখ্যাৰ সৈতে একেটা constant সংখ্যা যোগ বা বিয়োগ কৰি পাওয়া যায়।
Example: 2, 5, 8, 11, 14… 😎 step size = 3
Joke: কেনেকৈ AP party কৰে? Step by step, হা-হা! 😂
AP-ৰ ধৰণ
- Increasing AP: d>0, উদাহৰণ: 1,3,5,7,…
- Decreasing AP: d<0, উদাহৰণ: 20,15,10,5,...
- Constant AP: d=0, উদাহৰণ: 5,5,5,5,…
Fun fact: Increasing AP মানে numbers ৰ morning coffee ☕, decreasing AP মানে afternoon nap 😴!
গুণাবলী (Properties)
- AP-ৰ nth term:
Tn = a + (n-1)d - Sum of n terms:
Sn = n/2 [2a + (n-1)d] - Common difference:
d = T2 - T1 - Midterm property: Middle term = average of first and last term (যদি odd terms আছে)
Joke: AP midterm exam? 😆 Don’t worry, the middle always helps you balance!
সূত্ৰসমূহ
- nth term:
Tn = a + (n-1)d - Sum of n terms:
Sn = n/2 [2a + (n-1)d] - Common difference:
d = T2 - T1 - Middle term (odd n):
T(middle) = (a + l)/2
Joke: d যেন একmagic wand—step by step সব solve! ✨
উদাহৰণ
উদাহৰণ ১: 5, 8, 11,… Find T15 → 5 + (15-1)*3 = 5+42=47 😎 easy step by step
উদাহৰণ ২: Sum of first 20 terms of 2,5,8,… → Sn = 20/2[4+57]=10*61=610 🎉
উদাহৰণ ৩: Find d: 7,10,13,… → d=3 ✅
Fun Joke: AP student never gets lost—they follow the steps! 😂
অনুশীলনী প্ৰশ্ন (50)
50 questions with step-by-step descriptive answers (fun & kid-friendly):
- AP: 3,7,11,… T15 → 3+(15-1)*4=59 😎
- Sum 20 terms 2,5,8,… → 610 ✅
- Find d: 15,20,25,… → d=5 ✨
- AP: 1,4,7,… T25 → 73 🎉
- Sum 50 terms 1,2,3,… → 1275 ✅
- AP: 8,12,16,… T12 → 52 🥳
- Sum 10 terms 3,6,9,… → 165 🍭
- Find missing term: 5,__ ,13,17 → 9 😎
- AP: 7,10,13,… Sum first 15 terms → 315 🎯
- AP: 2,5,8,… T20 → 59 ✅
- Sum 20 terms 1,3,5,… → 590 ✨
- Find d: 4,7,10,… → d=3 ✅
- AP: 10,14,18,… T10 → 46 🎈
- Sum 12 terms 2,5,8,… → 222 ✅
- Find missing term: 3,__ ,11,15 → 7 😎
- AP: 5,9,13,… Sum 20 terms → 870 🎉
- AP: 1,5,9,… T30 → 117 ✅
- Sum 15 terms: 2,6,10,… → 450 🎯
- Find d: 12,18,24,… → d=6 ✅
- AP: 7,11,15,… Sum 25 terms → 1375 🥳
- AP: 2,7,12,… T18 → 2+(18-1)*5=87 ✅
- Sum 30 terms: 3,6,9,… → 1395 ✨
- AP: 4,10,16,… T20 → 4+19*6=118 🥰
- Find d: 50,45,40,… → d=-5 😎
- AP: 1,4,7,… Sum first 50 terms → 6375 🎉
- AP: 5,10,15,… T40 → 5+39*5=200 ✅
- Sum 15 terms 3,7,11,… → 555 ✨
- Find d: 100,90,80,… → d=-10 🥳
- AP: 7,14,21,… T25 → 7+24*7=175 ✅
- Sum 10 terms 5,10,15,… → 275 🎯
- AP: 2,9,16,… T20 → 2+19*7=135 🥰
- Find d: 12,15,18,… → d=3 ✅
- AP: 6,13,20,… Sum 12 terms → 12/2[6+83]=6*89=534 🎉
- AP: 5,10,15,… T30 → 5+29*5=150 ✅
- Sum 25 terms 1,4,7,… → 25/2[2+73]=25*37.5=937.5 ✨
- Find d: 18,22,26,… → d=4 🥳
- AP: 2,6,10,… T50 → 2+(50-1)*4=198 ✅
- Sum 40 terms 1,5,9,… → 40/2[2+157]=20*159=3180 🎯
- AP: 7,12,17,… T15 → 7+14*5=77 🥰
- Find missing term: 3,8,__ ,18 → 13 ✅
- AP: 10,20,30,… Sum 50 terms → 50/2[10+500]=25*510=12750 ✨
- AP: 1,3,5,… T100 → 1+(100-1)*2=199 🥳
- Sum 60 terms 2,4,6,… → 60/2[4+118]=30*122=3660 🎉
- AP: 5,8,11,… T45 → 5+44*3=137 ✅
- Find d: 50,60,70,… → d=10 😎
- AP: 2,7,12,… Sum 25 terms → 25/2[4+112]=25*58=1450 ✨
- AP: 3,6,9,… T35 → 3+34*3=105 🎯
- Sum 15 terms 2,5,8,… → 450 🥰
- Find missing term: 7,14,__ ,28 → 21 ✅
- AP: 6,11,16,… T20 → 6+19*5=101 🎉
- AP: 1,2,3,… Sum 50 terms → 50/2[2+49]=25*51=1275 ✨
- Find d: 100,95,90,… → d=-5 🥳
- AP: 5,15,25,… Sum first 40 terms → 40/2[10+395]=20*405=8100 ✅
- AP: 2,5,8,… T70 → 2+(70-1)*3=209 🎯
- Sum 30 terms 3,7,11,… → 30/2[6+126]=15*132=1980 🥰
- Find d: 1,4,7,… → d=3 ✅
- AP: 8,16,24,… T25 → 8+24*8=200 🎉
মুখ্য টিপস & Short Tricks
- Middle term (odd n) = average of first and last term ✅
- Sum of n terms = n/2*(first + last) যদি last term জানা থাকে 🥰
- Remember: d can be negative (decreasing AP) ✨
- Shortcut: For large n, always calculate (n-1)*d first, then add a 😎
- Fun Joke: AP students always step carefully, they don’t skip numbers! 😂
