00:01
Hello everyone, let us look into the equation here the height of an object after t seconds is given as f of t equal to minus 16 t square plus 90 t plus 5.
00:14
Now, the maximum height the object will attain.
00:19
So, which is to find this we have to differentiate this function.
00:22
So, f dash of t is equal to minus 32 t plus 90 which is equal to 0.
00:30
Hence, t equal to 90 by 32 we can have the value for this as 2 .8125 seconds.
00:40
So, hence in 2 .8125 seconds the function that is the object will attain its maximum height.
00:49
Now, substitute t as 2 .8125 in f of t.
00:55
So, we may have f of t is equal to minus 16 times 2 .8125 the whole square plus 90 times 2 .8125 plus 5 which is equal to 131 .5625.
01:12
So, from this maximum height attained equal to 131 .5625 feet.
01:21
The second question the number of seconds before the object will hit the ground...