graphs/functions HELP C3
Maths and statistics discussion, revision, exam and homework help.
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Re: graphs/functions HELP C3You need to work on your English. I presume you want to sketch the graph of y=(x+3)^2-5(Original post by godblessyousir)
(x+3)^2-5 why isnt the graph at -5 in the y axis and crossing 3 at the x axis? please help how i draw out this graph.
The minimum point of the curve will be at (-3, -5) Put x=0 and you should be able to write down the intercept on the y-axis. -
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Re: graphs/functions HELP C3why would it be(Original post by godblessyousir)
(x+3)^2-5 why isnt the graph at -5 in the y axis and crossing 3 at the x axis? please help how i draw out this graph.
expand the bracket and you will have ax^2 + bx + c and the graph will cross the y-axis at c
then factorise to find where it crosses the x-axis
all you can tell from the completed square is the minimum point -
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Re: graphs/functions HELP C3intercept on y axis is 4(Original post by steve2005)
You need to work on your English. I presume you want to sketch the graph of y=(x+3)^2-5The minimum point of the curve will be at (-3, -5) Put x=0 and you should be able to write down the intercept on the y-axis. -
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Re: graphs/functions HELP C3Correct and the curve will be symmetrical. So you now have 3 points.(Original post by godblessyousir)
intercept on y axis is 4 -
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Re: graphs/functions HELP C3i have y axis intercept=4 and minimum point is -3, -5 how do i work out where it crosses the x axis's(Original post by steve2005)
Correct and the curve will be symmetrical. So you now have 3 points. -
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Re: graphs/functions HELP C3how do i work out x intercepts its not 3 how do i work them out(Original post by TenOfThem)
why would it be
expand the bracket and you will have ax^2 + bx + c and the graph will cross the y-axis at c
then factorise to find where it crosses the x-axis
all you can tell from the completed square is the minimum point -
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Re: graphs/functions HELP C3The curve passes through (0,4) (-3, -5) and (-6,4) If you are simply doing a sketch these three points should be sufficient.(Original post by godblessyousir)
how do i work out x intercepts its not 3 how do i work them out -
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Re: graphs/functions HELP C3set the expression = 0(Original post by godblessyousir)
how do i work out x intercepts its not 3 how do i work them out -
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Re: graphs/functions HELP C3then i get to x^2+6x=-4 ...(Original post by TenOfThem)
set the expression = 0 -
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Re: graphs/functions HELP C3i need to draw the graph so i can work out its range for x ER so i need the x values please show me how i get them(Original post by steve2005)
The curve passes through (0,4) (-3, -5) and (-6,4) If you are simply doing a sketch these three points should be sufficient. -
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Re: graphs/functions HELP C3What was the original question? IF you want the range of the function then f(x)>-5 ( The greater symbol should be greater or equal)(Original post by godblessyousir)
i need to draw the graph so i can work out its range for x ER so i need the x values please show me how i get them -
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Re: graphs/functions HELP C3yh but how did u get the -5 for the x(Original post by steve2005)
What was the original question? IF you want the range of the function then f(x)>-5 ( The greater symbol should be greater or equal) -
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Re: graphs/functions HELP C3(Original post by godblessyousir)
yh but how did u get the -5 for the x
PLEASE paste the ORIGINAL question. -
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Re: graphs/functions HELP C3by completing the square, write f(x)=x^2+6x+4 in form (x+a)^2+b(Original post by steve2005)
PLEASE paste the ORIGINAL question.
sketch the graph of y=f(x) and state its range for x ER -
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Re: graphs/functions HELP C3Simple(Original post by godblessyousir)
by completing the square, write f(x)=x^2+6x+4 in form (x+a)^2+b
sketch the graph of y=f(x) and state its range for x ER
f(x)=x^2+6x+4
f(x)=(x+3)^2-9+4
f(x)=(x+3)^2-5
Range of f(x) greater/equal to -5
Sketch of curve passing through (-6, 4), (-3,-5) and (0, 4) No need to find where curve crosses x-axis.Last edited by steve2005; 23-09-2012 at 20:54. -
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Re: graphs/functions HELP C3but how do u know its -5?(Original post by steve2005)
Simple
f(x)=x^2+6x+4
f(x)=(x+3)^2-9+4
f(x)=(x+3)^2-5
Range of f(x) greater/equal to -5
when i get x its -5.2 etc etc long number, u can get the answer without sketching? how is this -
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Re: graphs/functions HELP C3the completed square gave the minimum point(Original post by godblessyousir)
but how do u know its -5?
when i get x its -5.2 etc etc long number, u can get the answer without sketching? how is this -
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Re: graphs/functions HELP C3(Original post by godblessyousir)
but how do u know its -5?
when i get x its -5.2 etc etc long number, u can get the answer without sketching? how is this
Completing the square has several uses. One of the uses is to find the maximum or minimum turning point. In this case the curve is U shaped and the bottom of the curve is at (-3, -5).
