energetic Posted March 12, 2011 Report Share Posted March 12, 2011 HEY look at this and help find the equation of the tangeent to each of the following curves at the point indicated by the value of x.Y=6(square root sign)x , where x=4 Reply Link to post Share on other sites More sharing options...
Drake Glau Posted March 12, 2011 Report Share Posted March 12, 2011 (edited) I have not done this. I googled and it made sense soooo here it goes 6sqrtX=6x^(1/2)Derivative being nx^n-1 so (1/2)6x^[(1/2)-1]Giving you 3x^(-1/2) which is the same thing as 3/x^(-1/2) which is the same thing as 3/sqrtxDerivative will give you the slope of the tangent which in this case would be 3/sqrt4=1.5To create an equation you need some point on that line. You have x=4. Plug that in to the ORIGINAL equation to find your Y which would be 6sqrt4 or 12. So now you have (4, 12) as your pointy-12=1.5(x-4)y-12=1.5x-6y=1.5x+6SUMMARY: Edited April 13, 2011 by Drake Glau 1 Reply Link to post Share on other sites More sharing options...
nametaken Posted March 13, 2011 Report Share Posted March 13, 2011 (edited) Need help with this, thanks:Find the area bounded by the curves:y= 2+x-x^2y= x^2-3x+2I just don't get the top-bottom thing. Edited March 13, 2011 by nametaken Reply Link to post Share on other sites More sharing options...
dessskris Posted March 13, 2011 Author Report Share Posted March 13, 2011 (edited) there you go nametaken Edited March 13, 2011 by Desy ♫ edited the last line.. I read 2*(2^2)/3 HAHA so stupid Reply Link to post Share on other sites More sharing options...
Keel Posted March 13, 2011 Report Share Posted March 13, 2011 (edited) Need help with this, thanks:Find the area bounded by the curves:y= 2+x-x^2y= x^2-3x+2I just don't get the top-bottom thing. I got something different.there you go nametaken Your method was right, your last line wasn't. I think you forgot to divide the 16 by two when you transformed the sixths into thirds. Edited March 13, 2011 by Keel 2 Reply Link to post Share on other sites More sharing options...
nametaken Posted March 21, 2011 Report Share Posted March 21, 2011 Question:In a game of Scrabble, Dalene has the seven letters A, D, E, k, O, Q and S. She picks two of these letters at random.a) What is the probability that one is a vowel and the other is the letter D?In my textbook it says the answer is 1/14. Thanks. Reply Link to post Share on other sites More sharing options...
Keel Posted March 22, 2011 Report Share Posted March 22, 2011 Question:In a game of Scrabble, Dalene has the seven letters A, D, E, k, O, Q and S. She picks two of these letters at random.a) What is the probability that one is a vowel and the other is the letter D?In my textbook it says the answer is 1/14. Thanks.P(D)=1/7P(vowel after getting a D)=3/61/7 x 3/6 = 3/42 = 1/14 Reply Link to post Share on other sites More sharing options...
Drake Glau Posted April 13, 2011 Report Share Posted April 13, 2011 (edited) So I need to differentiate and I'm working on it, get an answer, and it's completely wrong. I don't know what i'm doing apparently but this is the only problem in this section that has given me troubles. Any help would be good And I don't know how to upload the pretty math or whatever so here's a word doc instead Calc Help Upload.docx Edited April 13, 2011 by Drake Glau Reply Link to post Share on other sites More sharing options...
Slovakov Posted April 13, 2011 Report Share Posted April 13, 2011 (edited) Your first 2 steps are ok, but in the 3rd, better split it into 2 fractions and then it'l be easier to put the values from the nominator to denominator (after this operations the denominators of these 2 fractions rather won't be the same).I know it seems confusing, but I'll try to paste the wroking here Edited April 13, 2011 by Slovakov 1 Reply Link to post Share on other sites More sharing options...
Drake Glau Posted April 13, 2011 Report Share Posted April 13, 2011 (edited) Yea, not what the book says I don't know where they are getting this.I'm getting (x3 + 1 - 3x2x1/3)/[3x2/3(x3 +1)2]If that all makes sense. How do you make your math pictures? I'm tired of all these brackets...Book says my denominator is right, but it's also saying the numerator is 1-8x3 Edited April 13, 2011 by Drake Glau Reply Link to post Share on other sites More sharing options...
Slovakov Posted April 13, 2011 Report Share Posted April 13, 2011 (edited) I wrote it in Word and just made a print screen. Then extracted in Paint what I needed and here it is I made all the pictures to my portfolio this way. Edited April 13, 2011 by Slovakov Reply Link to post Share on other sites More sharing options...
ILM Posted April 13, 2011 Report Share Posted April 13, 2011 (edited) Here it is, it has a long solution, but i numbered the steps so you can told me the step that you don't understand. Edited April 13, 2011 by Summer Glau no text speak please =) 2 Reply Link to post Share on other sites More sharing options...
Markee Posted April 14, 2011 Report Share Posted April 14, 2011 Say. . .I've got a quick question, Tangent to the curve y=x3(x-2)2 has the coordinates (-1,-9) which meets Normal to the same curve at (1,1) at the point P. Find the coordinates of P. So, I just wanted to ask if you can either show me how step by step what needs to be done OR just give me the formula to do so.Thank you very much. Reply Link to post Share on other sites More sharing options...
dessskris Posted April 14, 2011 Author Report Share Posted April 14, 2011 Find the equation of the tangent first. Find dy/dx when x=-1 (gradient of tangent).Find the equation of the normal. Find dy/dx when x=1 (gradient of tangent). The gradient of normal is its negative reciprocal.Solve both equations simultaneously to get coordinates of P. 1 Reply Link to post Share on other sites More sharing options...
Markee Posted April 14, 2011 Report Share Posted April 14, 2011 (edited) (stupid remark)Ohhh yeaa...I feel like an idiot for forgetting those *facepalm* Thanks you very much!...Oh hang on...Should I use the Chain and Product Rule for this, btw? Edited April 14, 2011 by MARK10 Reply Link to post Share on other sites More sharing options...
dessskris Posted April 14, 2011 Author Report Share Posted April 14, 2011 doh I never memorised the names of the rules hahammm yes apparently. use product & chain rules. Reply Link to post Share on other sites More sharing options...
Markee Posted April 14, 2011 Report Share Posted April 14, 2011 So Product rules first then the Chain rule, yes? Reply Link to post Share on other sites More sharing options...
ILM Posted April 14, 2011 Report Share Posted April 14, 2011 Because you want to use product rule, then you should differentiate (x-2)^2 to differentiate it you will use chain rule. Reply Link to post Share on other sites More sharing options...
Markee Posted April 14, 2011 Report Share Posted April 14, 2011 (edited) I give up. I will do this last minute. So then I can focus more. But I have managed to figure it out So when dealing with equations like that that needs to use both either product rule or quotient rule, you use the chain rule first, then use the answer of that to apply the respective problem rule of it?How do you differentiate (x-2)2???? Edited April 16, 2011 by Desy ♫ Reply Link to post Share on other sites More sharing options...
dessskris Posted April 14, 2011 Author Report Share Posted April 14, 2011 1 Reply Link to post Share on other sites More sharing options...
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