The height s metres of a mass thrown vertically upward at a time t seconds given by
S=40t-13t2
Show when 25m= 40t - 13t2, 13t2 - 40t + 25 = 0
There is something about what you do to one side you have to do to the other?
The height s metres of a mass thrown vertically upward at a time t seconds given by
S=40t-13t2
Show when 25m= 40t - 13t2, 13t2 - 40t + 25 = 0
There is something about what you do to one side you have to do to the other?
No. This should be $\displaystyle 13t^2- 40t+ 25= 0$ which has, by the quadratic formula, solutions
$\displaystyle \frac{40\pm\sqrt{1600+ 1300}}{26}= \frac{40\pm\sqrt{2900}}{26}$.
(1)+(2) : $\displaystyle -26t_2=0 \Rightarrow t_2=0$
hence :
$\displaystyle 40t=25 \Rightarrow t=\frac{5}{8}$