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3 years ago

What is the value of the expression |a + b| + |c| when a = –3, b = 7, and c = –15?

1 answer:

3 0

We know:
$|a|= \left\{\begin{array}{ccc}a&if\ a \ \textgreater \ 0\\0&if\ a=0\\-a&if\ a \ \textless \ 0\end{array}\right\\\\|2|=2\\|0|=0\\|-3|=3$

$|a+b|+|c|$
substitute a = -3; b = 7; c = -15
$|-3+7|+|-15|=|4|+15=4+15=19$

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R (-3,1) and S (-1,3) are points on a circle. If RS is a diameter, find the equation of the circle.

ELEN [110]

Answer:

$\sf (x+2)^2+(y-2)^2=2$

Step-by-step explanation:

If RS is the diameter of the circle, then the midpoint of RS will be the center of the circle.

$\sf midpoint=\left(\dfrac{x_s-x_r}{2}+x_r,\dfrac{y_s-y_r}{2}+y_r \right)$

$\sf =\left(\dfrac{-1-(-3)}{2}+(-3),\dfrac{3-1}{2}+1 \right)$

$\sf =(-2, 2)$

Equation of a circle: $\sf (x-h)^2+(y-k)^2=r^2$

(where (h, k) is the center and r is the radius)

Substituting found center (-2, 2) into the equation of a circle:

$\sf \implies (x-(-2))^2+(y-2)^2=r^2$

$\sf \implies (x+2)^2+(y-2)^2=r^2$

To find $\sf r^2$ , simply substitute one of the points into the equation and solve:

$\sf \implies (-3+2)^2+(1-2)^2=r^2$

$\sf \implies 1+1=r^2$

$\sf \implies r^2=2$

Therefore, the equation of the circle is:

$\sf (x+2)^2+(y-2)^2=2$

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2 years ago

4 movie tickets cost $48. At this rate with is the cost of 5 movie tickets

cupoosta [38]

60 dollars, because each movie ticket cost 12$.

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3 years ago

Read 2 more answers

Fill in the gaps in the arithmetic sequence -3, _ ,_ , _, _, _ 12

lord [1]

Answer:

-0.5, 2, 4.5, 7, 9.5

Step-by-step explanation:

The given terms are 6 apart, so the common difference is 1/6 of their difference:

d = (12 -(-3))/6 = 15/6 = 5/2 = 2.5

Add 2.5 to each term to get the next one. Then the sequence is ...

-3, -0.5, 2.0, 4.5, 7.0, 9.5, 12

8 0

3 years ago

Find the unknown length in the right triangle 27cm and 13 cm

Phoenix [80]

use pythagoras:

${c}^{2} = \: {b}^{2} - {a}^{2}$

c^2 = (27)^2 - (13)^2

c^2 = 560

c = 23.6643....cm

3 0

3 years ago

Tan(2 sin^-1 0.4) Find the Exact value

stiv31 [10]

Answer:

tan(2u)=[4sqrt(21)]/[17]

Step-by-step explanation:

Let u=arcsin(0.4)

tan(2u)=sin(2u)/cos(2u)

tan(2u)=[2sin(u)cos(u)]/[cos^2(u)-sin^2(u)]

If u=arcsin(0.4), then sin(u)=0.4

By the Pythagorean Identity, cos^2(u)+sin^2(u)=1, we have cos^2(u)=1-sin^2(u)=1-(0.4)^2=1-0.16=0.84.

This also implies cos(u)=sqrt(0.84) since cosine is positive.

Plug in values:

tan(2u)=[2(0.4)(sqrt(0.84)]/[0.84-0.16]

tan(2u)=[2(0.4)(sqrt(0.84)]/[0.68]

tan(2u)=[(0.4)(sqrt(0.84)]/[0.34]

tan(2u)=[(40)(sqrt(0.84)]/[34]

tan(2u)=[(20)(sqrt(0.84)]/[17]

Note:

0.84=0.04(21)

So the principal square root of 0.04 is 0.2

Sqrt(0.84)=0.2sqrt(21).

tan(2u)=[(20)(0.2)(sqrt(21)]/[17]

tan(2u)=[(20)(2)sqrt(21)]/[170]

tan(2u)=[(2)(2)sqrt(21)]/[17]

tan(2u)=[4sqrt(21)]/[17]

7 0

3 years ago