A ball is 4 feet above the ground when Tyrese throws it into the air. Use the quadratic equation 0=−t2+3t+4 to find how much tim
2 answers:
Answer:
Step-by-step explanation:
This quadratic models the parabolic motion equation
where h is the height of the object after the motion occurs, a is the pull of gravity, v(i) is the initial vertical velocity of the object, and h(i) is the height from which the object was initially launched. If we are looking for when the ball hits the ground, h = 0, because the height of an object on the ground has no height at all (or 0 height). To find the time the object was in the air, factor the quadratic and solve for the values of t.
Two factors of 4 that add up to be 3 and multiply to be 4 are -1 and 4. So t=-1 and t = 4. Since we know that time can never be negative, then t = 4 seconds.
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Geometry is best done with squared distances. The squared distance from an arbitrary point (x,y) to the vertical line x=2 is
We equate that to the squared distance of (x,y) to the focus (-2,0):
We could call that done. A more standard form might be
Answer:
The mean is 9.65 ohms and the standard deviation is 0.2742 ohms.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
10% of all resistors having a resistance exceeding 10.634 ohms
This means that when X = 10.634, Z has a pvalue of 1-0.1 = 0.9. So when X = 10.634, Z = 1.28.
5% having a resistance smaller than 9.7565 ohms.
This means that when X = 9.7565, Z has a pvalue of 0.05. So when X = 9.7565, Z = -1.96.
We also have that:
So
The mean is
The mean is 9.65 ohms and the standard deviation is 0.2742 ohms.