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3 years ago

Verify the identity: 2 sec^2 x − 2 sec^2 x sin^2 x − sin^2 x − cos^2 x = 1

1 answer:

8 0

$\mathrm{Solving}\: \mathrm{prove\:2\sec ^2\left(x\right)-2\sec ^2\left(x\right)\sin ^2\left(x\right)-\sin ^2\left(x\right)-\cos ^2\left(x\right)=1}\\steps \\2\sec ^2\left(x\right)-2\sec ^2\left(x\right)\sin ^2\left(x\right)-\sin ^2\left(x\right)-\cos ^2\left(x\right)=1\\\mathrm{Manipulating\:left\:side}\\2\sec ^2\left(x\right)-2\sec ^2\left(x\right)\sin ^2\left(x\right)-\sin ^2\left(x\right)-\cos ^2\left(x\right)\\=-1+2\cos ^2\left(x\right)\sec ^2\left(x\right)\\=1$ Answer:

Step-by-step explanation:

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3 years ago

Geometry math question please help

stiks02 [169]

You need this key result: in any polygon, the sum of the interior angles is

$(n-2)\times 180$

where $n$ is the number of sides of the polygon.

Your polygon has seven sides, and the measures of all angles are given. So, we can write

$2x+4x+4x+4x+4x+2x+10x = (7-2)\times 180$

Again, we've simply written that the sum of all interior angles is the number of sides, minus two, times 180.

We can simplify both sides: we sum like terms on the left hand side, and we easily compute the right hand side:

$30x = 5\times 180 = 900$

and we can solve this equation for $x$ by dividing both sides by 30:

$x = \cfrac{900}{30} = 30$

Finally, the required angles is $2x = 2\times 30 = 60$

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2 years ago

36=2+(-12.4)<br> please helpssss

Nikolay [14]

I believe the answer is 36= -10.4!
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8 0

3 years ago

Read 2 more answers

Determine whether a probability distribution is given. If a probability distribution is given, find its mean and standard deviat

drek231 [11]

Answer:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 0*0.031 +1*0.156+ 2*0.313+3*0.313+ 4*0.156+ 5*0.031 = 2.5$

We can find the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 0^2*0.031 +1^2*0.156+ 2^2*0.313+3^2*0.313+ 4^2*0.156+ 5^2*0.031 =7.496$

And we can calculate the variance with this formula:

$Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246$

And the deviation is:

$Sd(X) = \sqrt{1.246}= 1.116$

Step-by-step explanation:

For this case we have the following probability distribution given:

X 0 1 2 3 4 5

P(X) 0.031 0.156 0.313 0.313 0.156 0.031

The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.

The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).

We can verify that:

$\sum_{i=1}^n P(X_i) = 1$

And $P(X_i) \geq 0, \forall x_i$

So then we have a probability distribution

We can calculate the expected value with the following formula:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 0*0.031 +1*0.156+ 2*0.313+3*0.313+ 4*0.156+ 5*0.031 = 2.5$

We can find the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 0^2*0.031 +1^2*0.156+ 2^2*0.313+3^2*0.313+ 4^2*0.156+ 5^2*0.031 =7.496$

And we can calculate the variance with this formula:

$Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246$

And the deviation is:

$Sd(X) = \sqrt{1.246}= 1.116$

6 0

3 years ago

What is the difference between a defined and an undefined term in Geometry?

Flura [38]

The difference between defined and an undefined term in Geometry is that defined terms can be combined with each other or an undefined term, and by doing this, there is another term defined. For example, an angle is a combination of two rays, which is an undefined term. Undefined term on the other hand is used to define other terms.

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3 years ago