๐️MTS101. BINOMIAL THEOREM
*BINOMIAL THEOREM*
There are some subtopics which will make us better understand this topic. And they are:-
➕ FACTORIAL
➖ PERMUTATION
➗ PASCAL TRIANGLE
✖️ BINOMIAL THEOREM
๐ฐ COMBINATION
๐บ Binomial Theorem itself
_Lets treat them one after the other_
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*FACTORIAL*
Its denoted by !
And It is the multiple of terms from a given term to the lowest counting number
E.g 3!= 3×2×1
But note: 0! = 1! =1๐
*Example*
1. Calculate 5! / 2!
Ans:-
5*4*3*2*1 / 2*1
Then you'll be left with 5*4*3
= *60* ✅
2.Calculate 10! × 3! / 8!
Show workings
Try that
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Since we now understand factorial better, this will then lead us to Permutation
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➖ *PERMUTATION*
*PERMUTATION*
_General formula_
log ) โฟPr = n! / (n-r)!
*Note:* a. n is always greater than r๐
b. Both can't be negative
*Examples*
1. Calculate ⁵P₂?
Ans:-
5! / (5-2)!
= 5! /3!
= *20* ✅
2. Solve ⁹P ₁₀?
*Incorrect*✅ because r can't be greater than n
3. Solve ⁵P₃₋โ = 120
Ans:-
5! / (3-x)! = 120
So since 5! = 120
That's
120/ (5-(3-x))! = 120
using arithmetics
You'll arrive at :
1/ (2+x)! = 1
Therefore
(2+x)! = 1
Since 1! = 1
So (2+x)! = 1!
Factorial will then cancel
2+x = 1
*x = -1✅*
Now we understand this
++++++++++++++++++++++
➗ *PASCAL TRIANGLE*
There is a diagram for this. Observe it and understand it.
Let's treat some examples on it.
Note: you can only use pascal Triangle if the power is not more than 7.๐
*Example*
1. *Expand (x + 2)³ using Pascal Triangle*
Ans:
= x³2⁰ + x²2¹ + x¹2² + x⁰2³
= x³ + 2x² + 4x¹ + 8
This isn't all cos we're using Pascal Triangle
Therefore it'll be coefficient of power 3 since the question is (x +2)³
= 1,3,3,1
Using pascal Triangle
So you'll the add to this
= x³ + 2x² + 4x¹ + 8
= 1x³ + 3(2x²) + 3(4x¹) + 8
*= x³ + 6x² + 12x¹ + 8✅*
I guess this is explanatory
2. *Expand (x - 2)³ using Pascal Triangle*
Ans:
You'll take same process as first but๐ค instead of using directly, it'll be (x + (-2))³
= x³(-2)⁰ + x²(-2)¹ + x¹(-2)² + x⁰(-2)³
= x³ - 2x² + 4x¹ - 8
Coefficients of power 3
= 1x³ - 3(2x²) + 3(4x¹) - 8
*= x³ - 6x² + 12x¹ - 8✅*
*EXERCISE*
Solve the following using pascal Triangle
1. (2x + y)⁴
2. (3 - x)³
3. (x + y)⁶
Guys guess what๐
We've started the next subtopic.
Pascal Triangle method is still same as Binomial Expansion
++++++++++++++++++++
✖️ *BINOMIAL EXPANSION*
Like I said it's same as Pascal Triangle✍️
××××××××××××××××××××××
๐ฐ *COMBINATION*
Permutation method already opened our eyes to this.
_General formula_
โฟCr = n! / (n-r)! r!
*Examples*
1. 5C3 ?
= 5!/ (5-3)! 3!
=5!/ 2! 3!
= 5×4/2
= *10* ✅
2. 5C7 ?
Ans: *incorrect*✅ because r can't be greater than n
3. *Expand (x + 2)³ using combination method*
Solution:-
³C₀x³2⁰ + ³C₁x²2¹ + ³C₂x¹2² + ³C₃x⁰2³
Finish it up
4. Using Combination method
Expand (2x + y)⁴
_To be continue_
Written by:
Mr. Peter Olabiyi
✍️ *FLASHPEE EDUCATIONAL TEAM*
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