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#31
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||@sibgakhan :
Salam, but let me try to solve it, though i dont know much about pure maths. f(x)= x^2 -x-1 g(x)= 3/x now fog(x)= f { g(x) } = f ( 3/x ) replace x by 3/x in f(x) fog(x) = (3/x)^2 - (3/x) - 1 = (9/x^2) -3/x -1 The above expression can be simplified easily , taking LCM as x^2, = 9 -3x - x^2 ------------ x^2 Domain of f (x) = { all real numbers } Domain of g (x) = { all real numbers except 0 } Domain of fog(x) = { all real numbers except 0} Lim x^3 -5x^2 + 6x / ( x^2 -9) x--->3 Solution : Applying limit to every factor, we get Lim x^3 - Lim 5x^2 + Lim 6x / ( x^2 -9) x-->3 x-->3 x-->3 The limit Lim 6x / ( x^2 -9) is in (c /0) form, so requires L hospital rule x-->3 so taking d/dx to 6x / ( x^2 -9) in denominator and nominator separately, we get, 6/ (2x-9) now putting value an applying limit, we get Lim x^3 - Lim 5x^2 + Lim 6/ (2x-9) x-->3 x-->3 x-->3 = 3^3 - 5(3)^2 + 6 /( 2*3 -9) = 27 - 45 -2 = -20 03. 7< ( 1-2x) ≤ 10 can be broken to two in equalities => 7< 1-2x ||||||||| 1- 2x ≤ 10 => 7-1 < -2x ||||||||| => -2x ≤ 10-1 => 6< -2x ||||||||| => -2x ≤ 9 => -6 > 2x ||||||||| => 2x > -9 => -3 > x ||||||||| => x > -4.5 which means between -∞ , -3 ||||||||| which means between -4.5 , ∞ when plotted together. __-9/2------4-------3_____-2_____-1_____0____ 1_____2_____3______4___ |
The Following 2 Users Say Thank You to j87ibz For This Useful Post: | ||
sahibakhushik89 (Sunday, May 29, 2016), sibgakhan (Saturday, October 30, 2010) |
#32
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Q#01
Solve the two sided inequality and show the solution on real line 7 < 1-2x ≤ 10 Solution: => 7 < 1-2x ≤ 10 multiply through out by (-) => -10 ≤ 2x-1 <-7 => -9 ≤ 2x < -7 Divide through out by 2 => -9/2 ≤ x < -7/2 Hence the resultant solution is semi close semi open interval [-9/2 , -7/2) on real line. Q#03 Simplify, then apply the rules of limit to evaluate lim x->3 x3(power3)-5x2(power2)+6x/x2(power2)-9 Solution: lim x->3 {x3(power3)-5x2(power2)+6x/x2(power2)-9} --------> {c/0 form} (Applying Lop-ital) Differentiating both denominator and nominator w.r.t 'x' => lim x->3 {3x2(power2)-10x+6/2x} Now applying limt => {3*(3^2)-10*3+6}/2*3 => {27-30+6}/6 => 3/6 => 1/2 Ans
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sibgakhan (Monday, November 01, 2010) |
#33
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Maths!
@ Sibgakhan
Q#01 Solve the two sided inequality and show the solution on real line 7 < 1-2x ≤ 10 Solution: => 7 < 1-2x ≤ 10 multiply through out by (-) => -10 ≤ 2x-1 <-7 => -9 ≤ 2x < -7 Divide through out by 2 => -9/2 ≤ x < -7/2 Hence the resultant solution is semi close semi open interval [-9/2 , -7/2) on real line. Q#03 Simplify, then apply the rules of limit to evaluate lim x->3 x3(power3)-5x2(power2)+6x/x2(power2)-9 Solution: lim x->3 {x3(power3)-5x2(power2)+6x/x2(power2)-9} -------->(A) {c/0 form} L' Hospital Rule is applied only if function has the form either {0/0} or {∞/∞}. Now we proceed as follows => lim {x->3 x^3-5x^2+6x}/x^2 - 9 Nominator can be expanded as x^3-5x^2+6x = x^3-3x^2-2x^2+6x = x^2*(x-3)-2x*(x-3) = (x^2-2x)*(x-3) ---->(i) Also x^2 - 9 = (x+3)*(x-3) ------>(ii) Now using (i) and (ii) in (A) => lim x->3 {(x^2-2x)*(x-3)}/(x+3)*(x-3) => lim x->3 {(x^2-2x)}/(x+3) Applying limit => {3^2 -2*3}/3+3 => {9-6}/6 => 3/6 => 1/2 Ans Best Regards!
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He who asks is a fool for five minutes, but he who does not ask remains a fool forever! GOOD LUCK! |
#34
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how we can convert fraction part of a question into hours and min?
i mean 5 5/7 and 10 2/70 comtains how many hours and min and what the formula?? thanks
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#35
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Quote:
suppose you have to convert 5 5/7 seconds to minutes and hours then you may proceed as follows: 1 min = 60 sec =>60 sec = 1 min =>1 sec = 1/60 min =>5 5/7 sec= 5 5/7 * 1/60 min = 40/7 *1/60 min = 2/21 min 1 hour = 60 min = 60 * 60 sec = 3600 sec =>3600 sec = 1 hour =>1 sec = 1/3600 hr =>5 5/7 sec = 5 5/7 * 1/3600 hr = 40/7 * 1/3600 hr = 1/630 hr and if 5 5/7 is not in sec but days then it will be converted to min and hours as follows: 1 day = 24 hrs =>5 5/7 days = 5 5/7 * 24 hrs = 40/7 * 24 hrs = 137 1/7 hrs also 1 day = 24 hrs = 24 * 60 min = 1440 min => 5 5/7 days = 40/7 * 1440 min = 8228 4/7 min. |
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sibgakhan (Sunday, November 07, 2010) |
#36
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can anyone solve these questions...
1. If the area of rectangle increased by 69%, the length of arm of the rectangle should increase:
2. If the length of arms of rectangle increased by 5% and 7% respectively, then the area of rectangle should increase by: 3. Jack’s salary is 150% of Tom’s salary; Tom’s salary is 80% of Adam’s salary. If Adam’s salary is S, then what is the ratio of Jack’s salary to Adam’s salary: 5. The cost price of a toy is $50, but its offer price is 108%. After one week it is sold on 10% discount. What will be the cost of toy? 6. The cost of first 500 prints is $10, while after it, cost for each is (10-x/50). What will be X, if the total cost is $75 7. 45% of people of a town have brown hair, while 20% of people have brown eyes. Meanwhile 10% have both brown hair and brown eyes. How much people have neither brown hair nor brown eyes? 8. In a town an appeal for fund raising is made. People of the town respond to that in this way: 45% people contributed $40, 30% contributed $20 while rest contributes $2. If the total amount of people who contribute $2 is $300, then what will be the total? 9. if the mean of 10 items is -10 and sum of 6 items is 100. what is the mean of remaining items? 10. In 2009, Ali read 10 English and 7 French books. In 2010, his ratio of English buks is 3times french buks and he read 60% of french books in 2010 then how many books he read in 2010? 11. Ahmed buys a merchandise on commission of 25 paisa. if the cost price is Rs.20 what percentage of commission he received? 12. if the price of tea increases by 20%. suppose a consumer expenditure on tea is Rs.200. then by what percentage he should cut his consumption of tea so that 20% increase in price of tea does'nt effect on his original expenditure on tea? 13. The growth rate is increased by 25% from 2000 to 2010. if the growth in 2010 is "W". what was the growth on 2000? 14. A can do a piece of work in 20 days which A and B together can do in 12 days. B alone can do it in hw many days? 15. In an election one of the 2 candidates gets 40% of the total votes but he losses by 160 votes . what is the total number of votes? 16. Salma spent 1/10 of her income on clothes, 1/10 of the remaining on food, and 1/3 of the remaining on rental. if she left with Rs. 648 what is her total income? 17. The total no. of students in a class are 335250. if they are adjusted in a square class with equal rows and columns, only 9 are left behind. what is the no. of rows?
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Aalam-e-soz o saz main, wasl se barh ker hai firaaq Hijr me lazt-e-talb, wasl main marg-e-arzoo...!!! Last edited by sibgakhan; Wednesday, February 16, 2011 at 12:51 AM. |
#37
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1. If the area of rectangle increased by 69%, the length of arm of the rectangle should increase:
2. If the length of arms of rectangle increased by 5% and 7% respectively, then the area of rectangle should increase by: plz solve these questions urgently.
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Aalam-e-soz o saz main, wasl se barh ker hai firaaq Hijr me lazt-e-talb, wasl main marg-e-arzoo...!!! |
#38
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question 1
area = 100 ( 50 x 2) new area = 169 (increased by 69 percent ) 169 = 84.2 x2 84.5 - 50 = 34.5 34.5 /50 = 69 % this means arm length will also increase by same amount if other arm's length doesn't change . question 2 area = a x b = ab new area = 1.05a x 1.07b = 1.1235ab new area - old area = 1.1235-1 = .1235 = 12.35 % |
#39
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Q9 100+X/10=-10
X=-200 and the average of remaining items is -50 |
#40
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Quote:
I think problem has been mis-typed. Please mention the amount.
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