#$&* course Mth 173 2/27 6:16 p.m. 010. `query 10
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Given Solution: *&*& The given function has zeros at x = -2, 1, 5, so y = k (x+2)(x-1)(x-5). At x = 0 the function has value 2, so 2 = k (0+2)(0-1)(0-5), or 2 = 10 k. Thus k = .2 and the function is y = .2 ( x+2)(x-1)(x-5). ** &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& Self-critique (if necessary): The answer was -1/2(x+2)^2(x-2) I forgot its y=kx^p I did however catch the ""double zero"" where the graph touches but does not pass through the -2 x intercept. ------------------------------------------------ Self-critique Rating: ********************************************* Question: `q Query problem 1.6.14 5th ed; 1.6.15 4th ed; 1.6.15 (formerly 1.4.19) s = .01 w^.25 h^.75what is the surface area of a 65 kg person 160 cm tall? YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Your solution: Problem number 31 ""The DuBois formula relates a person's surface area s, in m^2, to weight w, in kg, and height h, in cm, by s=0.01w^(0.25) * h^(0.75) a) what is the surface area of a person who weighs 65 kg and is 160cm tall"" s= .01 * 65^0.25 * 160^0.75 S= .01 * 2.839411514 * 44.98730602 S= 1.277374747m^2 confidence rating #$&*: 3 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Given Solution: ** Substituting we get s = .01 *65^.25 *160^.75 = 1.277meters^2 ** &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& Self-critique (if necessary): What is this focus on this relating to the current topic? It seems like a straight forward, plug in information type deal to me. I do notice it is a polynomic formula. ------------------------------------------------ Self-critique Rating:
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Given Solution: ** Substituting the values we get 1.5 = .01 w^.25*180^.75 . Dividing both sides by 180: 1.5/180^.75 .01w^.25. Dividing both sides by .01: 3.05237 = w^.25 Taking the fourth power of both sides: w = 3.052^4 = 86.806 ** &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& Self-critique (if necessary): OK ------------------------------------------------ Self-critique Rating: OK ********************************************* Question: `q For 70 kg persons what is h as a function of s? YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Your solution: s = .01 * 70^.25 * h^.75 s = .028925076 * h^.75 h^.75 = s/.028925076 h = (s/.028925076)^(4/3) confidence rating #$&*: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Given Solution: ** Substituting 70 for the weight we get s = .01 *70^.25 h^.75 s = .02893 h^.75 s/.02893 = h^.75 34.60 s = h^.75 Taking the 1/.75 = 4/3 power of both sides: (34.60 s)^(4/3) = h h = 111 s^(4/3), approximately ** STUDENT QUESTION Ok don’t understand where the 4/3 comes from but do understand that you need this to establish the resultant. INSTRUCTOR RESPONSE To solve 34.60 s = h^.75 for h you need to take the 1/.75 power of both sides, which gives you (34.60 s)^(1/.75) = (h^.75)^(1/.75). The right-hand side becomes h^(.75 * (1/.75) ) = h^1 = h, so we have h = (34.60 s)^(1 / .75). Since 1 / .75 reduces to 4/3, we have h = (34.70 s)^(4/3). 1 / .75 = 4/3 for the same reason $1.00 / $.75 = 4/3 (ratio of four quarters to three quarters, where by 'quarter' I mean the coin we most commonly put into vending machines). More formally 1 / .75 means 1.00 / .75 = 100 / 75. Dividing numerator and denominator by 25 reduces this to 4/3. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& Self-critique (if necessary): I am not sure how you got the denominator to the numerator ------------------------------------------------ Self-critique Rating:1"