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3 years ago

12

Sin 70°cos 10°-cos 70°sin 10=√3/2

1 answer:

hoa [83]3 years ago

8 0

Let a =70° and b= 10° (and a-b=70-10 =60)
We have the following trigonometric identity:

sin(a-b) = sin(a).cos(b)-sin(b).cos(a) OR:
sin(70-10) = sin70.cos10 - sin10.cos70
But sin(70-10) = sin(60) and we know that sin(60°) =(√3)/2

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What is the value of y−5x−3for x = 2 and y = -4

arlik [135]

Answer

-17

<u>Explanation</u>

y−5x−3 for x = 2 and y = -4

We solve this question by substituting the values of y and x.

y−5x−3 = -4 - 5(2) - 3

= -4 - 10 -3

= -14 - 3

= -17

8 0

3 years ago

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The coordinates of the vertices of a polygon are (-2, 1). (-3, 3), (-1, 5), (2, 4), and (2, 1). What is the perimeter of the pol

kobusy [5.1K]

Answer:

$15.2\ units$

Step-by-step explanation:

step 1

Plot the vertices of the polygon to better understand the problem

we have

$A(-2, 1). B(-3, 3), C(-1, 5), D(2, 4),E(2, 1)$

using a graphing tool

The polygon is a pentagon (the number of sides is 5)

see the attached figure

The perimeter is equal to

$P=AB+BC+CD+DE+AE$

the formula to calculate the distance between two points is equal to

$d=\sqrt{(y2-y1)^{2}+(x2-x1)^{2}}$

step 2

<em>Find the distance AB</em>

$A(-2, 1). B(-3, 3)$

substitute in the formula

$d=\sqrt{(3-1)^{2}+(-3+2)^{2}}$

$d=\sqrt{(2)^{2}+(-1)^{2}}$

$d_A_B=\sqrt{5}=2.24\ units$

step 3

<em>Find the distance BC</em>

$B(-3, 3), C(-1, 5)$

substitute in the formula

$d=\sqrt{(5-3)^{2}+(-1+3)^{2}}$

$d=\sqrt{(2)^{2}+(2)^{2}}$

$d_B_C=\sqrt{8}=2.83\ units$

step 4

<em>Find the distance CD</em>

$C(-1, 5), D(2, 4)$

substitute in the formula

$d=\sqrt{(4-5)^{2}+(2+1)^{2}}$

$d=\sqrt{(-1)^{2}+(3)^{2}}$

$d_C_D=\sqrt{10}=3.16\ units$

step 5

<em>Find the distance DE</em>

$D(2, 4),E(2, 1)$

substitute in the formula

$d=\sqrt{(1-4)^{2}+(2-2)^{2}}$

$d=\sqrt{(-3)^{2}+(0)^{2}}$

$d_D_E=\sqrt{9}\ units$

$d_D_E=3\ units$

step 6

<em>Find the distance AE</em>

$A(-2, 1).E(2, 1)$

substitute in the formula

$d=\sqrt{(1-1)^{2}+(2+2)^{2}}$

$d=\sqrt{(0)^{2}+(4)^{2}}$

$d_A_E=\sqrt{16}\ units$

$d_A_E=4\ units$

step 7

Find the perimeter

$P=AB+BC+CD+DE+AE$

substitute the values

$P=2.24+2.83+3.16+3+4=15.23\ units$

Round to the nearest tenth of a unit

$P=15.2\ units$

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To the nearest whole number it would be 1

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3 years ago

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