The height h of an arrow in feet is modeled by h(t) = -16t2 + 63t + 4, where t is the time in seconds since the arrow was shot. How long is the arrow in the air?
so if I were you, I will find dh/dt = maximum of the resulting curve. Such maximum occurs ath the highest point of the given expression, where the velocity is zero. Then I proceed by solving dh(t)/dt = 0. This probably given me the value of t at this point, right? Then I assume that the time taken to arrive at this point corresponds to the value obtained at the maximum!
so do I first divide 63/-16?
No its a calculus question. U find the derivative of H(t) with respect to t. This gives you the velocity. Did you guys study calculus?
Not really. This is my first application question I have done for this section.
So where would i start solving this. Because I am really confused
So you never heard about the derivative or what?
no
ok lets see u might need to solve the h(t) = 0 and probably divide by 2 or something. This could give u the time it takes. Hang on a sec lemme read the question again.
how would you solve that? /.\ h(t)=0/2?
notice that the leading coefficient of the parabola equation is negative, thus is opening DOWNWARD, so |dw:1385502780263:dw|
Yes because the arrow would be falling
|dw:1385502891190:dw| those would be the x-intercepts, so set y = 0, and solve for "x", like for any quadratic equaation \(\bf h(t) = -16t2 + 63t + 4\implies 0 = -16t2 + 63t + 4\)
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