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Mathematics: Post your doubts here!

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f(x)= 6 (2x+3)^-1
f'(x) = -6 (2x+3)^-2 (2+0)
-12/(2x+3)^2
-[12/(2x+3)^2]
whatever the value of x, whether negative or positive, the whole square will make the entire bracket value positive. but the negative sign will always make the answer negative so f(x) is always a decreasing function.
 
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f(x)= 6 (2x+3)^-1
f'(x) = -6 (2x+3)^-2 (2+0)
-12/(2x+3)^2
-[12/(2x+3)^2]
whatever the value of x, whether negative or positive, the whole square will make the entire bracket value positive. but the negative sign will always make the answer negative so f(x) is always a decreasing function.

How did you get the highlighted thing? I mean once we get f(x)= 6 (2x+3)^-1 we differentiate it and get f'(x) = -6 (2x+3)^-2 ? Why there is ^-2(2+0) ???
 
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whenever we diffrenciate, first we diffrenciate the power as u did, thn we diffrenciate the term in the bracket
 
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f : x → ....6
...............2x + 3

y = f(x)
f-1 ( y ) = x

y= 6/ 2x + 3
2xy +3y = 6
x= (6-3y)/2y

f-1(x)= (6-3x)/2x

markscheme says it is:
f-1(x)= −6(2x+3)^-2


checking through substituition in both the equation, I find equation in ms to be wrong,
Dunno!

markscheme says -6(2x+3)^-2 *2
 
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stupid me. I saw it late... they put that 2 waayy ahead, never noticed.
 
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I think o got my problem...I dont know how to differentiate in fractions.

Can anybody explain it? Please? (my maths exam is tomorrow)

Thank You
 
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I think o got my problem...I dont know how to differentiate in fractions.

Can anybody explain it? Please? (my maths exam is tomorrow)

Thank You
jus bring the denominator in the numerator with negative power. and diffrentiate as u diffrentiate power and bracket as i stated above...
 
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Please can anyone help me out with these questions ?
 

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ans3) dy/dx = gradient
at that point, gradient is = 3/[1+2(1)]^2
= 1/3
equation is:
y-y1=m(x-x1)
y - 1/2 = 1/3 (x - 1)
3y - 3/2 = x - 1
3y = x + 1/2
 
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Unique840 Thanks for helping me:) but I don't think that's the correct answer for that question.
Please someone help me.:cry:
 
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Yes CAPTAIN I have the final answers but I don't know the way to solve it. That's the problem.
 
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CAPTAIN these are the answers/instructions:-
 

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