1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
tekilochka [14]
3 years ago
15

Prove that cos^3x+3cos2x= 4 (cos^6 x-sin^6x)

Mathematics
1 answer:
gavmur [86]3 years ago
5 0
But this isn't true... If x=\dfrac\pi2, you have

\cos^3\dfrac\pi2+3\cos\pi=0-3=-3
4\left(\cos^6\dfrac\pi2-\sin^6\dfrac\pi2\right)=4(0-1)=-4

but of course -3\neq-4.
You might be interested in
The cost of a daily newspaper varies from city to city. however, the variation among prices remains steady with a standard devia
Tanya [424]

First, we establish our hypothesis:

<span>Null hypothesis H0: μ = $1.00  </span>

Alternative hypothesis Ha: μ ≠ $1.00

<span>Let’s say X  = the sample average cost of a daily newspaper = 0.96</span>

u = population mean cost = 1.00

S = sample standard deviation = 0.18

Calculating for z value:

z = (X – u) / S

z = (0.96 – 1) / 0.18

z = – 0.222

From the standard distribution table at this z value, p-value = 0.4129

Since alpha = 0.01, the decision therefore is:

<span>Do not reject the null hypothesis because the p-value is greater than 0.01. There is enough evidence to support the claim that the mean cost of newspapers is $1. </span>

6 0
3 years ago
Help!!! Will give brainliest to correct answer.....
zlopas [31]
I believe the answer is C.

93.53 - 21.41 = 72.12

If you simplify C, its answer becomes equivalent to the answer of the original problem:

(90 - 20) + (3 - 1) + (0.5 - 0.4) + (0.03 - 0.01)

70 + 2 + 0.1 + 0.02

72.12
7 0
3 years ago
Can someone help me with these two please , i’ll cashapp
Pavel [41]
3. 180 - (53+68) = 59

The answer is B. 59°

4.
Part A: The measure of a is 70°.

Explanation: The angle sum in any triangle is 180°. 70 + 40 is 110. To find the final angle, subtract 110 from 180. 180 - 110 = 70

Part B: The length of x is 5m.

Explanation. The triangle is an isosceles triangle. We know this because the two angles on the base are equal. Since this is an isosceles triangle, the two longer sides are the same length. Therefore: x = 5 m.
5 0
2 years ago
What is 4(x−2+y)? I need help.
stepladder [879]

4x+4y-8

Hope this helps!

7 0
3 years ago
So this should be one of the last few ones
sergeinik [125]

Answer:

A

Step-by-step explanation:

Because you have to use the Pythagorean theorem to solve for this.

8 0
2 years ago
Other questions:
  • A certain system can experience three different types of defects. Let Ai (i = 1, 2, 3) denote the event that the system has a de
    10·1 answer
  • Please help!<br><br> Answers:<br> 15<br> 70<br> 55<br> 105
    14·1 answer
  • Identify the range of the function shown in the graph
    11·1 answer
  • 80,000 scientific notation
    5·1 answer
  • What is the value of x? Enter your answer in the box.
    15·1 answer
  • How to find the primeter of a quadrilateral
    8·1 answer
  • A sphere and a cylinder have the same radius and height. The volume of the cylinder is 30 m
    7·1 answer
  • Select two ratios that are equivalent to 7: 10.
    13·1 answer
  • Due to changing wind conditions, a pilot is able to fly 150 mph for the first third of the flying time of a trip, 175 mph for th
    5·2 answers
  • What is the probability of you picking a red apple from a bag of green apples
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!