Week 4 Practice Assignment Q3-1.

Sanit arora

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Nov 8, 2020, 5:30:03 AM11/8/20

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In Week 4, practice assignment Q3, after deducing the Area of the field in the form (72L - L^2), the formula to calculate the max area from this equation is given (-b^2/4a + c), why not (-b/2a)?

Malabika Guha Mustafi

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Nov 8, 2020, 5:39:42 AM11/8/20

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Q 3 or 12?

Sanit arora

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Nov 8, 2020, 6:17:50 AM11/8/20

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Sorry, Q12*.

Anand Iyer

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Nov 8, 2020, 6:24:11 AM11/8/20

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The formula used in the solution is unnecessarily complicated.

Instead do this, Find max.value of l using -b/2a. You'll get l = 36.

Now, substitute l = 36 into the area's equation, 72l - l^2

It will give the same answer, 1296 square metres.

Malabika Guha Mustafi

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Nov 8, 2020, 6:44:43 AM11/8/20

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Exactly.

Malabika Guha Mustafi

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Nov 8, 2020, 7:11:58 AM11/8/20

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We get , y= - square(b)/4a + c ( for maximum value or minimum value after putting x=-b/2a) as follows:-

y= a(xsquare ) + bx+c

= a. square(-b/2a) + b. (-b/2a) +c

=square(b)/4a - square(b)/ 2a + c

= - square(b)/4a + c [ if you can remember , it is direct formula to get maximum/minimum]

Sanit arora

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Nov 8, 2020, 8:08:27 AM11/8/20

to Discussion forum for Mathematics for Data Science I, Malabika Guha Mustafi, anandd...@gmail.com, Sanit arora

Got it. Thanks for clarifying.

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