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4 years ago

Prove that sin alpha × sin(90- alpha) - cos(90-alpha) × cos alpha

Mathematics

1 answer:

satela [25.4K]4 years ago

8 0

Answer:

It is equal to 0.

Step-by-step explanation:

I can simplify it as follows:

sinα sin(90 - α) - cos(90 - α)(cosα)

Now sin(90 -α) = cosα and cos(90 - α) = sinα) ( for α < 90)

So the expression becomes:

sinαcosα - sinαcosα

= 0 .

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It says find the surface area of the pyramid. and the answer if the surface area is.

Debora [2.8K]

Answer:

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3 years ago

Formula for the surface area of a cylinder, SA = 2ar2 + 2arh. Solve for h.

MakcuM [25]

Answer:

$h=\frac{SA-2\pi r^2}{2\pi r}$

Step-by-step explanation:

The formula for the surface area of a cylinder is:

$SA=2\pi r^2+2\pi rh$

And we want to solve for the height h.

First, subtract $2\pi r^2$ from both sides. This yields:

$2\pi rh=SA-2\pi r^2$

Now, divide both sides by $2\pi r$ . This yields:

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4 years ago

At the beginning of an environmental study, a forest covered an area of 1500km^2. Since then, the area has decreased by 6.3% eac

geniusboy [140]

The <em><u>correct answer</u></em> is:

$y=1500(0.937)^t$

Explanation:

An exponential function is of the form

$y=a\times b^x$ , where a is the initial population, b is 1 plus the amount of yearly change, and x is the number of years.

For our problem, a, the initial population, is 1500.

The yearly change is 6.3%; 6.3% = 6.3/100 = 0.063. Since it is decreasing, this is negative; 1+(-0.063) = 0.937.

We use t as the number of years.

This gives us

$y=1500(0.937)^t$

3 0

4 years ago

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FinnZ [79.3K]

Answer:

110 students walk or bike to school.

Step-by-step explanation:

48% of the 208 students walk, whereas 5% bike. Combining 48% and 5%, we get 53%.

53% of the total number, n, comes to 208 students.

This number is 0.53(208 students), or 110 students.

110 students walk or bike to school.

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3 years ago

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Alex787 [66]

Felt appears to be right triangles

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4 years ago

Read 2 more answers

Prove that sin alpha × sin(90- alpha) - cos(90-alpha) × cos alpha​

Prove that sin alpha × sin(90- alpha) - cos(90-alpha) × cos alpha