The tangent line to <em>y</em> = <em>f(x)</em> at a point (<em>a</em>, <em>f(a)</em> ) has slope d<em>y</em>/d<em>x</em> at <em>x</em> = <em>a</em>. So first compute the derivative:
<em>y</em> = <em>x</em>² - 9<em>x</em> → d<em>y</em>/d<em>x</em> = 2<em>x</em> - 9
When <em>x</em> = 4, the function takes on a value of
<em>y</em> = 4² - 9•4 = -20
and the derivative is
d<em>y</em>/d<em>x</em> (4) = 2•4 - 9 = -1
Then use the point-slope formula to get the equation of the tangent line:
<em>y</em> - (-20) = -1 (<em>x</em> - 4)
<em>y</em> + 20 = -<em>x</em> + 4
<em>y</em> = -<em>x</em> - 24
The normal line is perpendicular to the tangent, so its slope is -1/(-1) = 1. It passes through the same point, so its equation is
<em>y</em> - (-20) = 1 (<em>x</em> - 4)
<em>y</em> + 20 = <em>x</em> - 4
<em>y</em> = <em>x</em> - 24
Answer:
parte 1) | Superprof
1 Indica cuáles de las siguientes expresiones son monomios. En caso de ... 4 Encuentra el valor numérico del polinomio P(x) = x^3 + 3x^2 - 4x - 12 ... d) (10x – 5/4x³ + 5/2x² – 1/2) : (5x)
Let
C-------> the length of a circumference
C=2*pi*r-----> equation 1
we know that
in this problem-----> <span>the circumference of the foundation is 4 times the radius, increased by 114 ft
</span>so
C=4*r+114------> equation 2
(1)=(2)
2*pi*r=4*r+114------> 2*pi*r-4*r=114-----> r*[2*pi-4]=114---> r=114/[2*pi-4]
r=114/[2*pi-4]-----> 50 ft
the answer is
r=50 ft
Answer:
a) 
b) The pollution level at 4 o'clock in the afternoon is of 280 parts per million.
Step-by-step explanation:
The pollution level in the center of a city at 6 am is 30 parts per million and it grows in linear fashion by 25 parts per million every hour.
This means that the pollution in t hours after 6 am is given by:
, which is the answer to question a.
b. The pollution level at 4 o'clock in the afternoon
4 in the afternoon is 10 hours after 6 am, so this is y(10).
The pollution level at 4 o'clock in the afternoon is of 280 parts per million.
