## anonymous one year ago Let u = <-5, -3>, v = <-6, -1>. Find -3u + 5v. @hero @dan815 @nincompoop @mathstudent55 @wio @radar @undeadknight26

1. misty1212

HI!!

2. misty1212

multiply both entries in $$u$$ by $$-3$$ multiply both entries in $$v$$ by $$5$$ then add

3. anonymous

huh? @misty1212

4. misty1212

i don't really know another way to say it

5. misty1212

u has two numbers right?

6. anonymous

can u show me? @misty1212

7. misty1212

multiply each of them by $$-3$$

8. misty1212

$u=<-5,-3>\\ -3u=-3<-5,-3>=<15,9>$

9. misty1212

in other words, multiply each entry by $$-3$$

10. misty1212

repeat to find $5v=5<-6,-1>$

11. anonymous

so its <-30,-5> @misty1212

12. misty1212

yes

13. misty1212

14. anonymous

can u help me with another? @misty1212

15. misty1212

16. anonymous

yes i got <-15,4> @misty1212

17. misty1212

oops yes you are right sorry

18. anonymous

can u help me with another? @misty1212

19. misty1212

ok sure

20. anonymous

Find a • b. a = 4i + 3j, b = -4i + 4j -4 28 <-16, 12> <0, 7>

21. misty1212

is that a dot between them?

22. anonymous

i think it times

23. misty1212

i think it means the "dot product"

24. misty1212

$<4,3>\cdot<-4,4>=4\times (-4)+3\times 4$

25. misty1212

it is a number, not a vector

26. misty1212

$-16+12=-4$ in other words

27. anonymous

Find the first six terms of the sequence. a1 = -7, an = 2 • an-1 -7, -14, -12, -10, -8, -6 0, 2, -14, -12, -10, -8 -7, -14, -28, -56, -112, -224 -14, -28, -56, -112, -224, -448

28. anonymous

@misty1212

29. misty1212

start with $$-7$$

30. misty1212

then multiply it by 2 to get the next number

31. misty1212

$-7,-7\times 2,-7\times 2\times 2...$

32. misty1212

so this one $-7, -14, -28, -56, -112, -224$

33. anonymous

Find the standard form of the equation of the parabola with a focus at (0, 4) and a directrix at y = -4. y = 1 divided by 16x2 y2 = 16x y2 = 4x y = 1 divided by 4x2 @misty1212

34. misty1212

i would go with the first one want to check?

35. misty1212
36. misty1212

yup looks good

37. anonymous

Find an explicit rule for the nth term of the sequence. 3, -12, 48, -192, ... an = 3 • 4n - 1 an = 3 • 4n + 1 an = 3 • (-4)n - 1 an = 3 • (-4)n @misty1212

38. misty1212

see how the signs change?

39. anonymous

yes by -4 @misty1212

40. misty1212

so only $a_n=3(-4)^{n-1}$ makes any sense

41. anonymous

one last one? @misty1212

42. misty1212

kk

43. anonymous

Use graphs and tables to find the limit and identify any vertical asymptotes of the function.

44. misty1212

? vertical asymptote is where the denominator is zero, so $$x=5$$

45. anonymous

what is the limit @misty1212

46. misty1212

ooh i see

47. misty1212

limit is infinity $$\infty$$

48. misty1212

oh no oops

49. misty1212

try $$-\infty$$