PLEASE I NEED HELP WITH THESE TWO PROBLEMS

Suppose f is a continuous function on [-2, 2) such that

Leviafan [203]

Answer:

2. a and b only.

Step-by-step explanation:

We can check all of the given conditions to see which is true and which false.

a. f(c)=0 for some c in (-2,2).

According to the intermediate value theorem this must be true, since the extreme values of the function are f(-2)=1 and f(2)=-1, so according to the theorem, there must be one x-value for which f(x)=0 (middle value between the extreme values) if the function is continuous.

b. the graph of f(-x)+x crosses the x-axis on (-2,2)

Let's test this condition, we will substitute x for the given values on the interval so we get:

f(-(-2))+(-2)

f(2)-2

-1-1=-3 lower limit

f(-2)+2

1+2=3 higher limit

according to these results, the graph must cross the x-axis at some point so the graph can move from f(x)=-3 to f(x)=3, so this must be true.

c. f(c)<1 for all c in (-2,2)

even though this might be true for some x-values of of the interval, there are some other points where this might not be the case. You can find one of those situations when finding f(-2)=1, which is a positive value of f(c), so this must be false.

The final answer is then 2. a and b only.

4 0

3 years ago

Save me the headache

maxonik [38]

$(9\sin2x+9\cos2x)^2=81$

Taking the square root of both sides gives two possible cases,

$9\sin2x+9\cos2x=9\implies\sin2x+\cos2x=1$

or

$9\sin2x+9\cos2x=-9\implies\sin2x+\cos2x=-1$

Recall that

$\sin(\alpha\pm\beta)=\sin\alpha\cos\beta\pm\cos\alpha\sin\beta$

If $\alpha=2x$ and $\beta=\dfrac\pi4$ , we have

$\sin\left(2x+\dfrac\pi4\right)=\dfrac{\sin2x+\cos2x}{\sqrt2}$

so in the equations above, we can write

$\sin2x+\cos2x=\sqrt2\sin\left(2x+\dfrac\pi4\right)=\pm1$

Then in the first case,

$\sqrt2\sin\left(2x+\dfrac\pi4\right)=1\implies\sin\left(2x+\dfrac\pi4\right)=\dfrac1{\sqrt2}$

$\implies2x+\dfrac\pi4=\dfrac\pi4+2n\pi\text{ or }\dfrac{3\pi}4+2n\pi$

(where $n$ is any integer)

$\implies2x=2n\pi\text{ or }\dfrac\pi2+2n\pi$

$\implies x=n\pi\text{ or }\dfrac\pi4+n\pi$

and in the second,

$\sqrt2\sin\left(2x+\dfrac\pi4\right)=-1\implies\sin\left(2x+\dfrac\pi4\right)=-\dfrac1{\sqrt2}$

$\implies2x+\dfrac\pi4=-\dfrac\pi4+2n\pi\text{ or }-\dfrac{3\pi}4+2n\pi$

$\implies2x=-\dfrac\pi2+2n\pi\text{ or }-\pi+2n\pi$

$\implies x=-\dfrac\pi4+n\pi\text{ or }-\dfrac\pi2+n\pi$

Then the solutions that fall in the interval $[0,2\pi)$ are

$x=0,\dfrac\pi4,\dfrac\pi2,\dfrac{3\pi}4,\pi,\dfrac{5\pi}4,\dfrac{3\pi}2,\dfrac{7\pi}4$

5 0

3 years ago

Read 2 more answers

What is the slope of this equation?<br> y = 3x - 4

Rainbow [258]

Answer:

m=3 is the slope of this equation y=3x-4

6 0

3 years ago

Rewrite in simplest terms : <br> 9(-8d - 7 ) +6(d+7)

Pepsi [2]

Answer: -66d-21 I think.

Step-by-step explanation:

9(-8d-7<u>)</u>+6(d+7)

-72d-63+6d+42 Distributive Property

-72d+6d+-63+42 Combine Like Terms

-66d-21 Answer

8 0

3 years ago

An online photo services charge $20 to make a photo book with 16 pages each extra page cost a dollar 75 the cost to ship the com

Alisiya [41]

Answer:

The expression to determine the total cost in dollars is $y=25+0.75x$ .

Step-by-step explanation:

Given:

Service charge to make a photo book = $20

Cost per extra page = $0.75

Cost to ship the complete photo book = $5

We need to write expression to determine the total cost in dollars.

Solution:

Let the number of extra pages be denoted by 'x'.

Also Let the Total cost be denoted by 'y'.

Now we can say that;

Total cost will be equal to sum of Service charge to make a photo book and Cost per extra page multiplied by number of extra pages and Cost to ship the complete photo book.

framing in equation form we get;

$y=20+0.75x+5\\\\y=25+0.75x$

Hence the expression to determine the total cost in dollars is $y=25+0.75x$ .

3 0

3 years ago