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INateI

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A curve has d2y/dx2= 8x and the tangent at (-2, 5) makes an angle of 45degrees with the x axis. Find the equation of the curve?? Maths in Foscus 2 extension 1 excercise 2.12 qu 15.
 
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morganforrest

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lnatel said:
A curve has d2y/dx2= 8x and the tangent at (-2, 5) makes an angle of 45degrees with the x axis. Find the equation of the curve?? Maths in Foscus 2 extension 1 excercise 2.12 qu 15.
Click to expand...
dy/dx at x=-2 must equal 1 since m=tan45

Integrate 8x to get 4x^2 + C

Use the previosuly stated condition to discover C = -15

Integrate again to find the equation of the curve:
y= 4/3.x^3 - 15x + C

Use your conditions... when x=-2 y=5 to discover the value of C as -14.3333etc

Hence the equation of the curve is y= 4/3.x^3 - 15x - 43/3

:) :wave:
 
tanjin

tanjin

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morganforrest said:
dy/dx at x=-2 must equal 1 since m=tan45

Integrate 8x to get 4x^2 + C

Use the previosuly stated condition to discover C = -15

Integrate again to find the equation of the curve:
y= 4/3.x^3 - 15x + C

Use your conditions... when x=-2 y=5 to discover the value of C as -14.3333etc

Hence the equation of the curve is y= 4/3.x^3 - 15x - 43/3
Click to expand...
And this is why I do general. :eek:
 
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morganforrest

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tanjin said:
Oh, shup Morgan. 'sif i was supposed to know that!

Numbers scare me. :eek:
Click to expand...
35457451687561567453475368534533456393645354574516875615674534753685345334563936453545745168756156745347536853453345639364535457451687561567453475368534533456393645354574516875615674534753685345334563936453545745168756156745347536853453345639364535457451687561567453475368534533456393645354574516875615674534753685345334563936453545745168756156745347536853453345639364535457451687561567453475368534533456393645354574516875615674534753685345334563936453545745168756156745347536853453345639364535457451687561567453475368534533456393645354574516875615674534753685345334563936453545745168756156745347536853453345639364535457451687561567453475368534533456393645

I <3 Spam :wave:

Beginning timing how long it takes for this to be deleted!!!
 
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