How do I solve these trigonometric equations!!?

1 answer:

3 0

1) (sin x)(cos x) = 0 This means that either sin x = 0, or cos x = 0. Sin x = 0 when x = 0 or pi. cos x = 0 when x = pi/2 or 3pi/2. 2) cos2x + 2cosx + 1 = 0 First, expand cos2x. Simple trigonometric identity states that cos2x = (cos x)^2 - (sin x)^2.Now, substituting this equation, we get cos2x + 2cosx + 1 = (cos x)^2 - (sin x)^2 + 2cosx + 1. Note that we can now utilize the identity (cos x)^2 = 1 - (sin x)^2 to obtain (cos x)^2 + 2cosx + 1 - (sin x)^2 = 2(cos x)^2 + 2(cos x) = 0. Now, we can see that 2(cos x)^2 + 2(cos x) = 2(cos x)(cos x + 1) = 0. This is true when cos x = 0 or cos x + 1 = 0. Cos x = 0 when x = pi/2 or 3pi/2. cos x = -1 when x = pi. Therefore, x = pi/2, pi or 3pi/2.

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How do you simplify 7x×4y×2y^2

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The answer is: 56xy³
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Explanation:
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Find the "like terms"; which are:
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"4y" and "2y²"
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The remaining term is: "7x".
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The problem is a "multiplication problem" :
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7x * 4y * 2y² ; so start by multiplying the "like terms" :
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Then the remaining term is "7x";
so, multiply that by our obtained value: "8y³ " :
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Step-by-step explanation:

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<h3>Answer: Choice D) -6 < -5</h3>

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Explanation:

Let's go through the answer choices

A) This is false because -2 is actually larger than -5. Make a number line and you'll see that -2 is to the right of -5. Numbers on the right are larger than numbers on the left.
B) This is also false. The value 0 is smaller than 2. A number line might help show this.
C) Also false. It should be 4 > -4. Any positive number is always larger than any negative number.
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