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1 year ago

Tom simplified an expression in three steps, as shown below:

Mathematics

1 answer:

Ivan1 year ago

5 0

Answer: a

Step-by-step explanation: process of elimination basically.

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Evaluate the integral using the indicated trigonometric substitution. (use c for the constant of integration.) x^3 / sqrt x^2 +

slava [35]

$\displaystyle\int\frac{x^3}{\sqrt{x^2+49}}\,\mathrm dx$

Taking $x=7\tan\theta$ gives $\mathrm dx=7\sec^2\theta\,\mathrm d\theta$ , so that the integral becomes

$\displaystyle\int\frac{(7\tan\theta)^3}{\sqrt{(7\tan\theta)^2+49}}(7\sec^2\theta)\,\mathrm d\theta$
$=\displaystyle7^4\int\frac{\tan^3\theta\sec^3\theta}{\sqrt{49\tan^2\theta+49}}\,\mathrm d\theta$
$=\displaystyle7^3\int\frac{\tan^3\theta\sec^3\theta}{\sqrt{\tan^2\theta+1}}\,\mathrm d\theta$
$=\displaystyle7^3\int\frac{\tan^3\theta\sec^3\theta}{\sqrt{\sec^2\theta}}\,\mathrm d\theta$
$=\displaystyle7^3\int\frac{\tan^3\theta\sec^3\theta}{|\sec\theta|}\,\mathrm d\theta$

When $\sec\theta>0$ , we have

$=\displaystyle7^3\int\frac{\tan^3\theta\sec^3\theta}{\sec\theta}\,\mathrm d\theta$
$=\displaystyle7^3\int\tan^3\theta\sec^2\theta\,\mathrm d\theta$

and from here we can substitute $u=\tan\theta$ to proceed from here.

Quick note: When we set $x=7\tan\theta$ , we are implicitly enforcing $-\dfrac\pi2$ just so that the substitution can be undone later via $\theta=\tan^{-1}\dfrac x7$ . But note that over this domain, we automatically guarantee that $\sec\theta>0$ , so the absolute value bars can be dropped immediately.

6 0

2 years ago

Read the ques

Dafna11 [192]

Answer:

0.25feet

Step-by-step explanation:

The equation is not well written. Let the equation of the height be modelled as;

h = -16d²+8d+4

The velocity of the ball is zero at its maximum height.

Velocity = change in displacement/time

v = dh/dd

Differentiate

v = -32d+8

Since dh/dd = v = 0

0 = -32d+8

Add 32d to both sides

0+32d = 8

32d = 8

Divide both sides by 32

32d/32 = 8/32

d = 1/4

d = 0.25feet

Hence the maximum height of the tennis ball is 0.25feet

Note that the modeled equation was assumed. You can apply the same calculation to any equation given

3 0

2 years ago

I have no idea what I am doing. Here is one of my problems,

Alisiya [41]

You need to set up a linear graph. One side with gallons and the other with dollars. Point 1 will be at (1500, 2.10). Point 2 (1300, 2.95). Draw a straight line through these points in your graph and your graph will then give you the answers to your other questions.

3 0

2 years ago

Which two values of x are roots of the polynomial below?

Julli [10]

Answer:

B. and C.

Step-by-step explanation:

1. Set the polynomial equal to zero:

x² + 5x + 7 = 0

2. Plug the given values of a, b, and c into the quadratic formula:

$x=\frac{-5+-\sqrt{5^{2}-4(1)(7) } }{2(1)}$