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4 years ago

Please answer them

Mathematics

2 answers:

Dima020 [189]4 years ago

8 0

Answer:

(1) 3.424 to the nearest 100 is 0

(2) 6.534 rounded to the nearest 10 is 10

alexdok [17]4 years ago

7 0

1. The shop told the retailer 3.400
2. The children wrote 6.530 on their whiteboard

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Please helpppp!!!!!!!

vfiekz [6]

Answer:

read below

Step-by-step explanation:

If you know tangent of theta is 5/3 and it is in the 3rd quadrant, then you know the sides will be going in the negative direction and the real values of the sides would be -5/-3. You can use pythagorean theorem to figure out that the hypotenuse would be sqrt(5^2+3^2) = sqrt(34). Then you can use soh cah toa: sin = opp/hyp, cos=adj/hyp tan = opp/adj. You know that opp = -5, adj = -3, and hyp = sqrt(34) For cosine theta, it would be -3/sqrt(34) and csc is just 1/sin so csc would be hyp/opp = sqrt(34)/-5.

6 0

3 years ago

2cos5xcos3x+sinx=cos8x

harkovskaia [24]

It looks like your equation (it's not an identity) is

2 cos(5x) cos(3x) + sin(x) = cos(8x)

Recall that

cos(x + y) = cos(x) cos(y) - sin(x) sin(y)

cos(x - y) = cos(x) cos(y) + sin(x) sin(y)

==> 2 cos(x) cos(y) = cos(x + y) + cos(x - y)

so that

2 cos(5x) cos(3x) = cos(8x) + cos(2x)

Then the equation simplifies to

cos(8x) + cos(2x) + sin(x) = cos(8x)

cos(2x) + sin(x) = 0

Also recall that

cos(2x) = 1 - 2 sin²(x)

so the equation is quadratic in sin(x) and can be factorized:

1 - 2 sin²(x) + sin(x) = 0

2 sin²(x) - sin(x) - 1 = 0

(2 sin(x) + 1) (sin(x) - 1) = 0

Solve for x :

2 sin(x) + 1 = 0 or sin(x) - 1 = 0

sin(x) = -1/2 or sin(x) = 1

[x = arcsin(-1/2) + 2nπ or x = π - arcsin(-1/2) + 2nπ] or x = arcsin(1) + 2nπ

(where n is any integer)

x = -π/6 + 2nπ or x = -5π/6 + 2nπ or x = π/2 + 2nπ

4 0

3 years ago

Newton's law of cooling states that the temperature of an object changes at a rate proportional to the difference between its te

Eva8 [605]

Answer:

Step-by-step explanation:

As per Newton law of cooling we have temperature of a cooling object at time t is given by

T(t) = $T_s + (T_0-T_s) e^{-kt}$

where $T_s = 76: T_0 = 200$

When t=2.5, we have

$T(2.5) = 76+(100-76)e^{-2.5k} =180\\e^{-2.5k} =\frac{104}{24} =4.333\\k=\frac{ln4.333}{-2.5} =-0.5865$

Hence equation is

$T(t) = 76+24e^{-0.5865t}$

Using this we find that

$130=76+24e^{-0.5862t} \\e^{-0.5862t}=54\\t=1.59559$

i.e. At 1.6 seconds the coffee will reach a temperature of 130 degrees

3 0

3 years ago

The elementary school lunch menu repeats every 20 days ; the middle school lunch menu repeats every 15 days. Both schools are se

Vikki [24]

The trick to this question is the find the least common multiple of 20 and 15. You could do 20×3=60 and 15×4=60 as those both equal the same number yet you there are no other multiples they share before 60. So the next time the two schools will eat pizza on the same day again will be in 60 days. Hope this helps!

7 0

4 years ago

Angle DEF and angle FEG are supplementary. The measure of angle DEF = (9x +1) and the measure of angle FEG = (8x + 9). What is t

RUDIKE [14]

Supplementary angles are angles that are adjacent to each other and when summed to get a total of 180 degrees. In this case, DEF and FEG are supplementary. Thus the equation is 9x +1 + 8x + 9 = 180 = 17 x + 10; x then is equal to 10 so
<DEF = 9*10 +1 =91 degrees
<FEG = 8*10 + 9 = 89 degrees

3 0

3 years ago

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