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3 years ago

In the diagram below of triangle ABC, medians AD, BE and CF intersect at point G

Mathematics

1 answer:

Rudik [331]3 years ago

7 0

Answer:

DG = 16 cm

Step-by-step explanation:

DG is one- third of AD , then

DG = $\frac{1}{3}$ × 48 = 16

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Find an equation of the plane with the given characteristics. The plane passes through the points (4, 3, 1) and (4, 1, -7) and i

Minchanka [31]

Answer:

$3x - 4y + z = 1$

Step-by-step explanation:

Given

$Point\ 1 = (4,3,1)$

$Point\ 2 = (4,1,-7)$

Perpendicular to $8x + 7y + 4z = 18$

Required

Determine the plane equation

The general equation of a plane is:

$a(x-x_1) + b(y - y_1) + c(z-z_1) = 0$

For $n =$

$(x_1,y_1,z_1) = (4,3,1)$

$(x_2,y_2,z_2) = (4,1,-7)$

First, we need to determine parallel vector $V_1$

$V_1 =$

$V_1$ is parallel to the required plane

From the question, the required plane is perpendicular to $8x + 7y + 4z = 18$

Next, we determine vector $V_2$

$V_2 =$

This implies that the required plane is parallel to $V_2$

Hence: $V_1$ and $V_2$ are parallel.

So, we can calculate the cross product $V_1 * V_2$

$V_1 =$

$V_2 =$

$n = V_1 * V_2$

$V_1 * V_2 =\left[\begin{array}{ccc}i&j&k\\0&2&8\\8&7&4\end{array}\right]$

The product is always of the form + - +

So:

$V_1 * V_2 = i\left[\begin{array}{cc}2&8\\7&4\end{array}\right]$ $-j\left[\begin{array}{cc}0&8\\8&4\end{array}\right]$ $+k\left[\begin{array}{cc}0&2\\8&7\end{array}\right]$

Calculate the product

$V_1 * V_2 = i(2*4- 8*7) - j(0*4- 8*8) + k(0*7 - 2 * 8)$

$V_1 * V_2 = i(8- 56) - j(0- 64) + k(0 - 16)$

$V_1 * V_2 = i(-48) - j(- 64) + k(- 16)$

$V_1 * V_2 = -48i +64j - 16k$

So, the resulting vector, n is:

$n =$

Recall that:

$n =$

By comparison:

$a = -48$ $b = 64$ $c = -16$

Substitute these values in $a(x-x_1) + b(y - y_1) + c(z-z_1) = 0$

$-48(x-x_1) + 64(y - y_1) -16(z-z_1) =0$

Recall that: $(x_1,y_1,z_1) = (4,3,1)$

So, we have:

$-48(x-4) + 64(y - 3) -16(z-1) =0$

$-48x + 192 + 64y -192 - 16z +16 = 0$

Collect Like Terms

$-48x + 64y - 16z = 0 - 192 + 192 - 16$

$-48x + 64y - 16z = -16$

Divide through by -16

$3x - 4y + z = 1$

<em>Hence, the equation of the plane is</em> $3x - 4y + z = 1$ <em></em>

4 0

3 years ago

Mr. And mrs. Dorsey and their three children are flying to Springfield. The cost of each ticket is $179. Estimate how much the t

kicyunya [14]

Estimate to 200$ and multiply by 5 to get $1000 then $179 mulitiplied by 5 is $895

4 0

3 years ago

Read 2 more answers

The sum of 25 and y, multiplied by 2

notka56 [123]

Answer:

Step-by-step explanation:

25x2=50

hope this helps and is write but seems pretty good

5 0

3 years ago

Read 2 more answers

Given g(x)=-2x-3, then what is g(2m+7)

Whitepunk [10]

Answer:

-4m-17

Step-by-step explanation:

g(2m+7) = -2*(2m+7) -3

= -4m -14 -3

= -4m -17

8 0

3 years ago

For positive acute angles A and B it is known that tan A 15/8 and Cos B 12/37 find the value of Cos (A+b) being in simplest form

weqwewe [10]

Answer:

Step-by-step explanation:

Cos(A + B) = Cos(A)*Cos(B) - Sin(A)*Sin(B)

Find The Hypotenuse of A

Tan(A) = Opposite / Adjacent

Tan(A) = 15/8

Opposite = 15

Adjacent = 8

Hypotenuse = c

c^2 = opposite^2 + Adjacent^2

c^2 = 15^2 + 8^2

c^2 = 225 + 64

c^2 = 289

sqrt(c^2) = sqrt(289)

c = 17

Find the opposite of B

Adjacent = 12

Hypotenuse = 37

Opposite = b

adjacent^2 + opposite^2 = hypotenuse^2

12^2 + b^2 = 37^2

144 + b^2 = 1369

b^2 = 1369 - 144

b^2 = 1335

b = 35

Definitions

Sin(A) = Opposite / hypotenuse = 15/17

Sin(B) = opposite / hypotenuse = 35/37

Cos(A) = 8/17

Cos(B) = 12/37

Answer

Cos(A + B) = Cos(A)*Cos(B) - Sin(A)*Sin(B)

Cos(A + B) = 8/17 * 12/37 - 15/17*35/37

Cos(A + B) = 96/629 - 525/629

Cos(A + B) = -429/629

6 0

3 years ago