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3 years ago

8

Cho tam giác ABC vuông tại A < góc B=a chứng minh: a) 1+

le="tan^{2}" alt="tan^{2}" align="absmiddle" class="latex-formula">a= $\frac{1}{sin^{2}a }$
làm giúp mình với

1 answer:

dimaraw [331]3 years ago

8 0

<h3><u>L</u><u>H</u><u>S</u><u>:</u><u>-</u></h3>

$\\ \sf\longmapsto 1+tan^2A$

$\boxed{\sf tanA=\dfrac{sinA}{cosA}}$

$\\ \sf\longmapsto 1+\dfrac{sin^2A}{cos^2A}$

$\\ \sf\longmapsto \dfrac{cos^2A+sin^2A}{cos^2A}$

$\boxed{\sf cos^2A+sin^2A=1}$

$\\ \sf\longmapsto \dfrac{1}{cos^2A}$

$\\ \sf\longmapsto \dfrac{1}{1-sin^2A}$

$\\ \sf\longmapsto \dfrac{1}{1}-\dfrac{1}{sin^2A}$

$\\ \sf\longmapsto \dfrac{1}{sin^2A}$

Hence verified

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steposvetlana [31]

Answer:

Probability is 0.3506

Step-by-step explanation:

We are given

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standard deviation is 2.2 mm

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At x=9:

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we can plug values

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3 years ago

An observer on top of a 50-foot tall lighthouse sees a boat at a 7° angle of depression. To the nearest foot, how far is the boa

Yuri [45]

Answer:

407.22 foot is the boat from the base of the lighthouse

Step-by-step explanation:

Given the statement: An observer on top of a 50-foot tall lighthouse sees a boat at a 7° angle of depression.

Let x foot be the distance of the object(boat) from the base of the lighthouse

Angle of depression = $7^{\circ}$

$\angle CAB = \angle DCA = 7^{\circ}$ [Alternate angle]

In triangle CAB:

To find AB = x foot.

Using tangent ratio:

$\tan (\theta) = \frac{Opposite side}{Adjacent Base}$

$\tan (\angle CAB) = \frac{BC}{AB}$

Here, BC = 50 foot and $\angle CAB =7^{\circ}$

then;

$\tan (7^{\circ}) = \frac{50}{x}$

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$x = \frac{50}{\tan 7^{\circ}}$

$x = \frac{50}{0.1227845609}$

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3 years ago

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DENIUS [597]

Answer:

I just graphed it in desmos for you UvU

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3 years ago

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Ksivusya [100]

Answer:

Reflecting a point across the y-axis -> changes the sign of the x-coordinate

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Reflecting a point across the x-axis -> changes the sign of the y-coordinate

Step-by-step explanation:

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The rule to reflect a point across the y-axis is (-x, y), meaning that the x-coordinate's sign changes.
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2 years ago

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Round the answer as needed.

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3 years ago