Evaluate the dot product of (2 4) and (1 -2)

2 answers:

7 0

I'd suggest writing this as

<2, 4> dot <1, -2>. Another name for this is "scalar product."

Rule: <a,b> dot <c,d> = ac + bd

Thus,

<2, 4> dot <1, -2> comes out to (2)(1) + (4)(-2) = -6 (which is a scalar).

ahrayia [7]3 years ago

3 0

That would be 2*1 + 4*-2 = 2 - 8 = -6 Answer

You might be interested in

Solve -7x^2+x+9=-6x quadratic formula

myrzilka [38]

Answer:

$-7x^2+x+9=-6x$

$-7x^2+x+9+6x=-6x+6x$

$-7x^2+7x+9=0$

$quadratic\: formula$

$x_{1,\:2}=\frac{-7\pm \sqrt{7^2-4\left(-7\right)\cdot \:9}}{2\left(-7\right)}$

$\sqrt{-7^{2} -4(-7)\times9} =\sqrt{301}$

$x_{1,\:2}=\frac{-7\pm \sqrt{301}}{2\left(-7\right)}$

$\frac{-7+\sqrt{301}}{2\left(-7\right)}$

$=\frac{-7+\sqrt{301}}{-2\cdot \:7}$

$=\frac{-7+\sqrt{301}}{-14}$

$\frac{-7-\sqrt{301}}{2\left(-7\right)}$

$=\frac{-7-\sqrt{301}}{-2\cdot \:7}$

$=\frac{-7-\sqrt{301}}{-14}$

$answer=\frac{7+\sqrt{301}}{14}$

$OAmalOHopeO$

7 0

3 years ago

Can someone see if these are right?

qwelly [4]

I didn't get the same answers.

In this problem, 25 is your constant (the number of baby hats you already started out with).
26 will be affected by your variable, d, the number of days. With each day that passes, 26 more hats will be knit, so the expression 26d can be used.

Set h equal to the constant + hats made per day to create an expression that you can use to solve for h:
h = 26d + 25

Now, just plug the numbers in for d to get h:
When d = 2, h = 26d + 25 = 26(2) + 25 = 77
When d = 4, h = 26d + 25 = 26(4) + 25 = 129
When d = 7, h = 26d + 25 = 26(7) + 25 = 207
When d = 9, h = 26d + 25 = 26(9) + 25 = 259

Your answers should be:
77
129
207
259

5 0

3 years ago

Using whichever equation you prefer (part a, b, or c), find the speed of light in meters per second if a mass of 3 kilograms con

pav-90 [236]

$Given:\\m=3kg\\E=2.7\cdot 10^{17}J\\\\Find:\\c=?\\\\Solution:\\\\E=mc^2\\\\c^2= \frac{E}{m} \\\\c= \sqrt{\frac{E}{m}} \\\\c= \sqrt{ \frac{2.7\cdot 10^{17}J}{3} } = (2.7\cdot 10^{16} \frac{m^2}{s^2} )^{ \frac{1}{2} }=3\cdot 10^{8} \frac{m}{s}$