anonymous one year ago Write an equation of hte line, in point-slope form, that passes through the two given points. points(-15, 7)(5,-3) (posting picture of answers)

1. anonymous

2. anonymous

3. Jack1

m = y2-y1/x2-x1 = -10/20 = - 1/2 so yeah, that's the only one with an M value of -1/2

4. Jack1

id go C too ;)

5. anonymous

Yay! I get so happy when I get math questions right. :P I'm bad at math. I have 2 more(including this one) i'm not sure of

6. anonymous

this is the last one

7. sepeario

like @Jack1 did, or you could firstly work out the gradient, and substitute the values into a point gradient formula.

8. Jack1

a) $$\large y = -16x^2 +15 +110x$$ do you know how to find the derivative of this? (y')

9. anonymous

no..

10. Jack1

hmmm... k k well idk how else to do it, sorry so: $$\Large y = -16x^2 +15 +110x$$ $$\Large y = -16x^{\color{red}{2}} +110x^{\color{blue}{1}} +15x^\color{green}{0}$$ $$\Large y' = \color{red}{2} \times-16x^{\color{red}{2}-1} + \color{blue}{1} \times 110x^{\color{blue}{1}-1} +\color{green}{0} \times 15x^{\color{green}{0}-1}$$ $$\Large y' = \color{red}{-32x^1} + \color{blue}{110x^0} + \color{green}{0}$$ $$\Large y' = \color{red}{-32x^1} + \color{blue}{110}$$ this is the gradient

11. Jack1

|dw:1435739203953:dw|

12. Jack1

$$\large y′=−32x+110$$ gradient = 0 at the turning point (highest point) $$\large 0=−32x+110$$ $$\large -110=−32x$$ $$\large -110/-32=x$$ so the time it takes to get to the highest point = 110/32 = 3.44 seconds (ish)

13. Jack1

does this make sense? @kimberlyalice

14. anonymous

Yes it does

15. anonymous

Sorry, I had to go eat breakfast cause I'm fasting so it's really early in the morning.

16. Jack1

nah, chill, all good, i'm makin snacks now too, freakin starving sweet, so if it reaches the peak ht at 3.44 seconds... how long from when its fired to when it hits the ground?

17. anonymous

Would the peak height be about half the entire path of the object?

18. anonymous

19. Jack1

yeps, perfect so only 1 answer has 7 seconds

20. anonymous

That means I was right!! This is so exciting!

21. anonymous

THANK YOU!

22. Jack1

well... 1 sensible answer B is kinda low, sáll 3.4 feet isnt very high

23. Jack1

weait i didnt finish omg im so sorry :(

24. anonymous

It's okay. I jumped too quickly :)

25. anonymous

Is it A? The height is higher

26. Jack1

yep, a to prove: just plug x =3.44 into first equation y=−16x2+15+110x y = height = 204.06

27. anonymous

Ahh, I see! Thank you!

28. anonymous

Can you help me with the last one?

29. Jack1

b) ??? maybe, will try.... so the difference each time is -3 7... -3 = 4... -3 = 1... -3 = -2... etc... but it's supposed to be recursive... so doesnt that mean it eventually comes back to 7?

30. anonymous

I believe so..

31. UsukiDoll

Recursion is the process of choosing a starting term and repeatedly applying the same process to each term to arrive at the following term. Recursion requires that you know the value of the term immediately before the term you are trying to find.

32. Jack1

i'm out then, sorry :(

33. anonymous

can you help me @UsukiDoll

34. anonymous

it's okay @Jack1

35. Jack1

how do i medal u @UsukiDoll ? sorry ive given mine away for this q already

36. UsukiDoll

er.. who has medal who though?

37. UsukiDoll

and a user can't medal 2 people at the same time :/

38. anonymous

I can start a new question and you can give a medal @Jack1

39. UsukiDoll

k that sounds good.

40. Jack1

do it!