A toy rocket is launched off a 96-foot tall building. The rocket's height in feet h(t) is h(t) = -16t^2 + 80t + 96. Evaluate h(4). Explain what the answer means in terms of the toy rocket.
h(4)=-16(4)^2+80(4)+96 simplify that by using order or operations
at t=4, the height of the rocket is h(4) feet
order of operations*
does 16(4)^2 = 16 times 8 or 64^2?
ok i thought so
wait... when i solved it i got h(4) =652. is that correct?
i don't have a calculator
and i don't feel like doing the arithmetic by hand
don't you have a calculator on your computer?
yes but i don't like it
no, h(4) = 416-256 = 160
ohh right i forgot about the negative. thanks!!
now, they're asking me.... what is the toy rocket's maximum height? at what time does this occur?
how would i go about solving this one?
find the vertex of the parabola
write in h(x)=a(x-h)^2+k form the vertex is (h,k) the height is k
fmax i think
so could someone show me how to plug it into this formula? i'm lost :'/
you have to put in that form not plug it into that form
\[h(x)=(-16t^2+80t)+96 \] we need to factor out -16 out of first two terms
so divide both 80 and 16 by 8 to reduce the fraction 80/16
but 10/2 =5
so they both had the factor 16 in common
now complete the square inside that parenthesis
so what do we need to put in this blank to complete the square: \[t^2-5t+__\]
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