The best estimate of the population mean is the sample mean

first calculate the sum of all samples:
32+24+14+34+26+27+31+16+18+26=248
then divide by the amount of samples to get the samples mean: 248/10=24.8 miles per gallon

8 0

3 years ago

HELP ASAP TIMED !!!! What is the exact value of cos(c + d), given Sine c = StartFraction 24 Over 25 EndFraction for c in Quadran

Keith_Richards [23]

9514 1404 393

Answer:

Step-by-step explanation:

In the second quadrant, ...

c = 180° -arcsin(24/25) ≈ 106.26°

In the third quadrant, ...

d = 360° -arccos(-3/4) ≈ 221.41°

Then cos(c+d) = cos(327.67°) ≈ 0.84498

This is a positive irrational number, greater than 21/100, so the only reasonable choice is the last one:

$\dfrac{21+24\sqrt{7}}{100}\approx 0.84498$

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Perhaps you want to work this out using the trig identities.

cos(c) = -√(1 -sin(c)²) = -7/25

sin(d) = -√(1 -cos(d)²) = -(√7)/4

Then the desired cosine is ...

cos(c+d) = cos(c)cos(d) -sin(c)sin(d)

cos(c+d) = (-7/25)(-3/4) -(24/25)(-√7/4)

cos(c+d) = (21 +24√7)/100 . . . . matches choice D

8 0

3 years ago