Monday, 4 February 2013

INDICES & SURDS - The Mistake Fragment 2

Labels:
By Mr Johari

 Identify the mistakes shown below and post your corrections.
For the correction identify the correct rules.

 Find the algebra mistake: 
1.       mistake
2.      mistake
3.       mistake


4.      Find the algebra mistake: 
         mistake

5.     Find the algebra mistake: 
     mistake
Posted by at

19 comments:

  1. Wee Chang Han (章瀚19）4 February 2013 at 22:15

    1. e ^t^2e^t = e ^t^2+t
    2. 10(1.3)^t = 10 x 1.3^t
    3. e^-6+e^-2 = e
    4. square root + square root does not equal to a rational number. Instead, it must be multiplied.
    5. The square root applies all the values and integers it covers, not only the x.

    ReplyDelete
  2. MasonSim0984 February 2013 at 22:20

    1) e^t^2 x e^t is actually adding the index , not multiplying them so the answer is e^t^2 + t ( a^m x a^n = a^m )

    2) It is already in it's simplest form . We have to follow the order of operations before multiplying

    3)He assumed that when the bases are similar , we can add them together to combine them . The end product is e^-8 , this can only be achieved if the operation is multiplication

    4) Addition of 2 identical square roots will not remove the square root , only multiplication will do that .

    5) √x-1+h , In this case , the square root belongs to all the terms in it not just the x , therefore he can not just put the square root on x .

    ReplyDelete
  3. Shaun Ng4 February 2013 at 22:20

    1. He multiplied the power of e instead of adding it.
    e^t^2e^t = e^t^2+t

    2. He did not consider the t power to be part of 1.3 as a package when multiplying with 10
    10(1.3)^t cannot be simplified further

    3. He assumed that when adding same bases with power he should add the powers together. However, this cannot be simplified further and we should add powers together when it is multiplied not added.

    4. He though by adding square roots the square root would be removed. However, we must multiply two square roots of the same kind to remove the square root.

    1/ 2(Square root 2x+1)

    5. He took the square root out of -1 and h, but -1 cannot be square rooted and he is not allowed to take it out of h without squaring.

    (x-1+h-x+1)/h^2 = h/h^2 = h^-1

    ReplyDelete
  4. Owen Ong4 February 2013 at 22:21

    1. e^(t^2) x e^t ≠ e^(t^3) instead it is e^(t^2+t)

    2. This is wrong due to order of operations. (It should be power then multiplying) instead, it should be 1.3^t x 10

    3. e^-6 + e^-2 ≠ e^-8 . That only works if the sign is multiplication instead of addition. The expression could not be simplified to be any simpler.

    4. √2x+1 + √2x+1 ≠ 2x+1. This only works if the sign is multiplication instead of addition. This expression could not be simplified to be any simpler.

    5. √x-1+h ≠ √x -1+h , the square root should still remain for all the values inside it. This should also be applied to √x-1 ≠ √x -1

    ReplyDelete
  5. ryan tzn4 February 2013 at 22:23

    1. (The error is where the power should be t^2+1) e^t^2 x e^t = e^t^2 +t

    2. (The error is where he multiplied 10 to 1.3 to get 13 instead on multiplying the power first.) 10 x (1.3^t)

    3. (The addition sign cannot be used to add powers only the multiplication sign.) e^-6 x e^-2 = e^-8

    4.(√2x+1 + √2x+1 = 2x+1 only works if the sign is a multiplication sign.) √2x+1 x √2x+1 = 2x+1

    5. (All the terms under the square root are included in the square root and the square root can only be removed if squared. The person just removed the terms from under the square root without doing anything.) h/h^2

    ReplyDelete
  6. Chin_Wai KIt4 February 2013 at 22:24

    1) e^t^2 x e^t does not equal to e^t^3
    instead it should be e^t^2 + t

    2) 10(1.3)^t does not equal to 13^t
    Because one is suppose to complete the (1.3)^t portion first before multiplying by 10. The answer cannot be simplified any further.

    3) e^-6 + e^-2 does not equal e^-8 as the formula for adding powers should be a^m x a^n = a^m+n

    4) sqrt(2x+1) + sqrt(2x+1) does not equal to 2x+1
    Because to get 2x+1, one has to mulitply the two values sqrt(2x+1) with sqrt(2x+1)

    5) sqrt(x-1+h) is not equal to sqrt(x)-1+h as one cannot remove the values of -1 and +h as the two values also need to undergo sqrt.

    ReplyDelete
  7. ♪ Jemima ♫4 February 2013 at 22:24

    1) e^t^2 x e^t ≠ to e^t^3
    It should be:
e^t^2 x e^t = e^(t^2+t)

    2) 10(1.3)^t ≠ 13^t, 10(1.3)^t is the simplest form because t is unknown.

    3) e^-6 + e^-2 ≠ e^-8
    It should be e^-6 x e^-2 = e^-8

    4) √2x+1 + √2x+1 ≠ 2x+1
    It should be”
    √2x+1 + √2x+1 = 2(√2x+1)

    5) (-1+h) cannot be removed from the square root because -1≠√-1.

    ReplyDelete
  8. farrellnah4 February 2013 at 22:27

    1.Conceptual error e^(t^2) x e^t ≠ e^(t^2 x t). it should be e^(t^2+t)

    2. Conceptual error. This cannot be simplified any further. Based on the order of operations, 1.3 ^ t must be calculated first before multiplying the result by 10

    3.Conceptual error e^-6 + e^-2 cannot be simplified any further. The rule is used wrongly. The rule only applies for multiplication

    4. conceptual error. let 2x+1 = a. √a x √ a = a. Not √a + √a

    5. Conceptual error. When simplifying √(z-1+h), it should simplify to √x -1 +√h.

    ReplyDelete
  9. OOOP4 February 2013 at 22:28

    2) Already simplified, ^t belongs to 1.3, not 10(1.3)
    3)e^-6 + e^-2 != e^-8 as it is a plus sign, not a divide sign.
    4) Only works if it is a multiply sign, not a plus sign
    5) Square root applies to the whole of the term, not just x

    ReplyDelete
  10. j4 February 2013 at 22:28

    1. e^t^2 * e^t = e^(t^2+t)
    2. The 10 cannot be multiplied into the brackets before the power, as the power takes precedence. 10(1.3)^t = 10 * 1.3^t
    3. When adding indices with the same base, you do not add the powers. e^-6 + e^-2 = 1/e^6 + 1/e^2 = e^2+e^6 / e^8 (Adding fractions)
    4. The surds are being multiplied together, although the sign there is to add.
    5. The square root doesn't only cover the x, it also covers the -1+h. In the 2nd step, the square root is removed from the -1 and h, making the equation wrong.

    ReplyDelete
  11. Teh Howe Wee4 February 2013 at 22:30

    1. e^t^2 * e^t = e^t^2 + t
    2. You must expand the power first before doing multiplication, thus 10(1.3)^t = 10 x 1.3^t
    3. When adding indices you cannot just add the power, you first have to multiply flip the fraction and find a common denominator
    4.Addition of square roots wil not remove them only multiplication will
    5. Square roots covers -1 + h as well as x and in the equation -1 + h were removed.

    ReplyDelete
  12. Carissa4 February 2013 at 22:30

    1. a^n x a^m = a^n+m not a^m x n
    It should be e^t^2 x e^t = e^t^2+t.

    2. 10(1.3)^t is already in the simplest form.

    3. Adding of the powers can only happen when the bases are the same and when the bases are multiplied. Since this is addition and not multiplication, we cannot add the powers to get the answer.

    4. The multiplication of two square roots does not remove the square root.

    5. The square root belongs to the entire equation x-1+h and x-1 and not just x. Hence we are suppose to square root the entire equation and not just x.

    ReplyDelete
  13. Unknown4 February 2013 at 22:34

    1:=E^(T^2+1)
    2:already the simplest form
    3.already the simplest form
    4.already the simplest form
    5.(-1+h) cannot be removed from the square root because -1≠√-1.

    ReplyDelete
    Replies
    1. Nur Johari4 February 2013 at 23:37

      Please check - there are errors in all the solution

      Delete
  14. Unknown4 February 2013 at 22:36

    1. e^t^2*e^t=e^(t^2+t)
    2.10*[(1.3)^t]
    3.e^-6+e^-2
    4.1/2(√2x+1)
    5.the square root doesn't only cover x....

    ReplyDelete
  15. Unknown5 February 2013 at 02:45

    1. e^t^2 e^t=e^t^2+t

    2. the answer should be 10*1.3^t

    3. e^-6+e^-2=(1+e^4)/e^6

    4. √(2x+1)+√(2x+1)≠2x+1=1/2(√2x+1)

    5. √(x-1+h)-√(x-1)=√(x+h)÷√1-(√x÷1)≠(√x-1+h)-(√x-1)

    ReplyDelete
  16. Denzel Supriyadi5 February 2013 at 03:34

    1) It should be e^((t^2)+t) (Conceptual error should be adding indices not multiplying)
    2) 10*1.3^t (Conceptual error cannot multiply indices by base)
    3) e^-6+e^-2 should be left as that, cannot be simplified further (Conceptual error, cannot add indices together as it is just adding)
    4) Adding square roots will not get rid of the square root, only multiplication will do that....1/(2(2x+1)^1/2)
    5) Cannot just make the square root only to the value of x as it is applicable to the rest of the values within the square root

    ReplyDelete
  17. Lee Kai En5 February 2013 at 06:37

    1. The error he made was multiplying the indices together. They should be added together instead.
    2. He multiplied the bases. And, the power has more "priority" than the base so the brackets should be opened up first before multiplying anything.
    3. e^-6+e^-2 cannot be simplified further as they are being added together. The answer which he got, e^-8, can only be achieved when they are being multiplied together.
    4. Adding both the square roots will not be able to remove the square root.
    5. The square root applies to all of the terms not just x itself.

    ReplyDelete
  18. Isaac Gan5 February 2013 at 06:52

    1) e^t^2 e^t=e^t^2+t He was should add the indies instead of multiplying it.
    2) He should find out what (1.3)^t is first before multiplying by 10.
    3) You cannot add the power unless you multiply the terms together.
    4) Adding the square roots will not remove the square root ,the only way to get rid of the square root is to multiply by another identical surd.
    5) The squareroot applies to all the other terms too!




    ReplyDelete

Subscribe to: Post Comments (Atom)