All categories

3 years ago

Find a · b. |a| = 4, |b| = 7, the angle between a and b is 2π/3

Mathematics

1 answer:

galben [10]3 years ago

5 0

Answer:

-14

Step-by-step explanation:

a·b = |a|×|b|×cos(angle between them)

= 4×7×(-1/2)

= -14

You might be interested in

What are the factor pairs of 42?

Oksi-84 [34.3K]

42 can be

1 x 42, or
2 x 21, or
3 x 14, or
6 x 7 .

5 0

3 years ago

Read 2 more answers

I need help with question 2

Genrish500 [490]

Answer:

Find every possibility in which she has 2 matching letters.

Step-by-step explanation:

7 0

3 years ago

Anna007 [38]

Answer:

1) The correct option is C. (2) The correct option is D. (3) The correct option is B. (4) The correct option is D. (5) The correct option is D.

Step-by-step explanation:

The slope formula is

$m=\frac{y_2-y_1}{x_2-x_1}$

(1)

Two points are (-2,5) and (1,4).

$m=\frac{4-5}{1-(-2)}=\frac{-1}{3}tex]Therefore option C is correct.(2)Use the above mentioned formula for each pair of coordinates.[tex]m=\frac{10-13}{17-12}=\frac{-3}{5}$

$m=\frac{10-15}{13-16}=\frac{-5}{-3}=\frac{5}{3}$

$m=\frac{10-7}{3-0}=\frac{3}{3}=1$

$m=\frac{18-13}{8-11}=\frac{5}{-3}=\frac{-5}{3}$

Therefore option D is correct.

(3)

The pair of points (6, y) and (10, -1). The slope is $\frac{1}{4}$ .

$\frac{1}{4}=\frac{-1-y}{10-6}$

$\frac{1}{4}=\frac{-1-y}{4}$

$1=-1-y$

$y=-2$

Therefore option B is correct.

(4)

For vertical line the x coordinates always remains the same. Therefore when we subtract the same number we get zero in the denominator, therefore the value of slope is undefined for a vertical line.

Therefore option D is correct.

(5)

Two points from the table are (2,110) and (3,165).

$m=\frac{165-110}{3-2}=\frac{55}{1}$