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2 years ago

If cos2A=11/25, show that cosA=6/5√2

Mathematics

1 answer:

Hatshy [7]2 years ago

7 0

Answer:

it is not I think...

Step-by-step explanation:

Using the identity

$\cos(2a) = 2 \cos^2(a) - 1$

We can solve:

$2 \cos^2(a) - 1 = \frac{11}{25}$

$2 \cos^2(a) = \frac{36}{25}$

$\cos^2(a) = \frac{18}{25}$

$\cos(a) = \sqrt \frac{18}{25}$

$\cos(a) = \sqrt{ 2 \cdot \frac{3^2}{5^2} }= \frac35 \sqrt 2$

So whoever asked the question forgot the factor 2!!!

Or did I miss anything??

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A physics exam consists of 9 multiple-choice questions and 6 open-ended problems in which all work must be shown. If an examinee

katrin [286]

Answer: A) 1260

Step-by-step explanation:

We know that the number of combinations of n things taking r at a time is given by :-

$^nC_r=\dfrac{n!}{(n-r)!r!}$

Given : Total multiple-choice questions = 9

Total open-ended problems=6

If an examine must answer 6 of the multiple-choice questions and 4 of the open-ended problems ,

No. of ways to answer 6 multiple-choice questions

= $^9C_6=\dfrac{9!}{6!(9-6)!}=\dfrac{9\times8\times7\times6!}{6!3!}=84$

No. of ways to answer 4 open-ended problems

= $^6C_4=\dfrac{6!}{4!(6-4)!}=\dfrac{6\times5\times4!}{4!2!}=15$

Then by using the Fundamental principal of counting the number of ways can the questions and problems be chosen = No. of ways to answer 6 multiple-choice questions x No. of ways to answer 4 open-ended problems

= $84\times15=1260$

Hence, the correct answer is option A) 1260

5 0

3 years ago

the zeros of a parabola are -4 and 2, and (6, 10) is a point on the graph. which equation can be solved to determine the value o

natka813 [3]

Sure this question comes with a set of answer choices.

Anyhow, I can help you by determining one equation that can be solved to determine the value of a in the equation.

Since, the two zeros are - 4 and 2, you know that the equation can be factored as the product of (x + 4) and ( x - 2) times a constant. This is, the equation has the form:

y = a(x + 4)(x - 2)

Now, since the point (6,10) belongs to the parabola, you can replace those coordintates to get:

10 = a (6 + 4) (6 - 2)

Therefore, any of these equivalent equations can be solved to determine the value of a:

10 = a 6 + 40) (6 -2)

10 = a (10)(4)

10 = 40a

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2 years ago

Read 2 more answers

6+2[x+8]+3x+11+x help plzzzzz

Alex787 [66]

6+2(x+8)+3x+11+x
First you have to expand the brackets:
6+2x+16+3x+11+x
Now you group like terms (terms with the same or no variable):
2x+3x+x+11+16+6
And finally, combine like terms:
6x+33

Hope this helps :)

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2 years ago

Contrast and compare squares and rectangles

liberstina [14]

Answer:

I found this over the internet and hope it helps:

A rectangle is a quadrilateral with all four angles right angles. It follows form this that the opposite sides are parallel and of the same length. A square is a quadrilateral with all four angles right angles and all four sides of the same length.

Also note that a square is always a rectangle, but a rectangle is not always a square.

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2 years ago

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Pythagorean Theorem Word

diamong [38]

Answer:

40 miles

Step-by-step explanation:

In the attached diagram, Point A is the starting point and C is the end point. We want to determine the distance from A to C.

The path driven forms a right triangle in which AC is the hypotenuse.

We therefore use the<u> Pythagorean Theorem</u> to solve for the AC.