help with these problems  TOPIC_SOLVED

Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.

help with these problems

Postby netsfan549 on Wed Dec 19, 2012 5:32 pm

The height,s, in feet of a rock thrown upward at an initial speed of 68ft/s from a cliff 48 ft above the ocean beach is given by the function s(t) = -16t2(squared) + 68t + 48, where t is the time in seconds/ Find the maximum height above the beach that rock willl attain.

On wet concrete the stopping distance, s in feet of a car traveling at v miles per hour is given by the function s(v) = 0.0o6v2 (squared) + 1.4v. What is the mximum speed at which a car could be traveling and still stop at a sign 52ft away?

Find two numbers whose difference is 86 and whose product is a minimum..

I dont get the problems. Can someone show me how to do it? show me and did you get answer. I really appreciate it. Thank you!
netsfan549
 
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Re: help with these problems

Postby theshadow on Thu Dec 20, 2012 12:04 am

netsfan549 wrote:The height,s, in feet of a rock thrown upward at an initial speed of 68ft/s from a cliff 48 ft above the ocean beach is given by the function s(t) = -16t2(squared) + 68t + 48, where t is the time in seconds/ Find the maximum height above the beach that rock willl attain.

find the vertex (thats where the max/min of quads are)

netsfan549 wrote:On wet concrete the stopping distance, s in feet of a car traveling at v miles per hour is given by the function s(v) = 0.0o6v2 (squared) + 1.4v. What is the mximum speed at which a car could be traveling and still stop at a sign 52ft away?

put in 52 for s and solve

netsfan549 wrote:Find two numbers whose difference is 86 and whose product is a minimum.

they show how to set this up here then find the vertex
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Re: help with these problems  TOPIC_SOLVED

Postby buddy on Sat Dec 22, 2012 7:30 pm

netsfan549 wrote:The height,s, in feet of a rock thrown upward at an initial speed of 68ft/s from a cliff 48 ft above the ocean beach is given by the function s(t) = -16t2(squared) + 68t + 48, where t is the time in seconds/ Find the maximum height above the beach that rock willl attain.

complete the suqare or use the formula to get the vertex. h=t is the time of the max height. k=s is the max height.

netsfan549 wrote:On wet concrete the stopping distance, s in feet of a car traveling at v miles per hour is given by the function s(v) = 0.0o6v2 (squared) + 1.4v. What is the mximum speed at which a car could be traveling and still stop at a sign 52ft away?
52=0.06v^2+1.4v
solve for v.

netsfan549 wrote:Find two numbers whose difference is 86 and whose product is a minimum..

x-y=86, x-86=y, xy=x(x-86)=product
find vertex for max
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