Question

can someone plz check my answer?

Answer 1

http://prnt.sc/d9uf4q
http://prnt.sc/d9uf8q

Answer 2

@Astrophysics

Answer 3

@sooobored

Answer 4

@.Sam.

Answer 5

first one can easily be checked based off y-intercept
looks like there is already a check there

Answer 6

are you familar with the first derivative?
for d. the distance away from the punter is teh same as finding the roots of the given equation. you can either find it by factoring or by using the quadratic formula

Answer 7

@sooobored so is my last two answers are wrong?

Answer 8

well, i assumed the x mark means its wrong

Answer 9

yes i know the first derivative

Answer 10

didnt calculate it and check but i can if you want

Answer 11

sure plz check that one

Answer 12

i think that is what I am getting

Answer 13

f(x)=-16/1225 x^2 +7/5x +3/2
f'(x) = -32/1225 x +7/5

setting to zero
0= -32/1225 x +7/5
32/1225x=7/5

so it should reach maximum height when
x= 53.59375

plugging that back in
f(53.59375)= ...

wish i had matlab up and on this comp

Answer 14

yay its up, one sec

Answer 15

75.83125?

Answer 16

y= -16/1225(53.59375) +7/5(53.59375) +3/2

Answer 17

108.248... as distance

Answer 18

39.015625 as height

answers look good when rounded

Answer 19

but isn't the y vale for the maximum height ?

Answer 20

?

Answer 21

the equation you wrote is missing a square

Answer 22

oh

Answer 23

53.... ^2 +...

Answer 24

well this is what I get when I draw the graph

Answer 25

http://prntscr.com/d9ujrm

Answer 26

ok?
nothing wrong with that

Answer 27

39.02 as height

Answer 28

right?

Answer 29

i calculated 39.015625 as height
its the same when rounded

Answer 30

yep

Answer 31

did you not see it above?

Answer 32

i do

Answer 33

oh, then is there any other questions?

the values you inputted are correct

Answer 34

but now how did you figure out part d can you plz explain that a bit?

Answer 35

we need to find the x-intercept right? make y=0?

Answer 36

oh, well, i cheated and used matlab
roots([ -16/1225 7/5 3/2])

Answer 37

what you would actually do would be use the quadratic formula

\[\frac{-b \pm \sqrt{b^2-4ac}}{2a}\]

Answer 38

assuming you dont want to try and factor it

Answer 39

i suggest memorizing it, its really useful to know off the top of your head for tests

Answer 40

ok thanks a lot