Step-1

Title: Trigonometry equations

Grade: 1300-a Lesson: S3-L5

Explanation: Hello Students, time to practice and review the steps for the problem.

Lesson Steps

Step Type Explanation Answer

1

Problem

Solve the equation: \$sin2x + 2 cosx sinx = \sqrt3\$.

2

Step

The given equation is

\$sin2x + 2 cosx sinx = \sqrt3\$

3

Formula:

\$sin2x = 2 sinx cosx\$.

4

Step

Now plug the formula in the given equation

\$2sinx cosx + 2 cosx sinx = \sqrt3\$

5

Step

Let take the common term 2cos⁡(x)sin⁡(x) then simplify it

\$2sinx cosx( 1 + 1) = \sqrt3\$
\$ 2(2cosx sinx) = \sqrt3\$

6

Step

Simplify the equation

\$2 sin(2x) = \sqrt3\$
\$sin(2x) = \sqrt(3) /2\$

7

Step

Now, we need to find the angles 2x where the sine is equal to the \$\sqrt(3)/2\$. This occurs when \$2x = (2(pi))/3 and (pi)/3\$.

8

Step

Now, we solve for x:

\$2x = (2pi)/3\$ and \$2x = (pi)/3\$

\$x = (pi)/3\$ and \$x = (pi)/6\$

9

Step

So, the solutions for the equation are \$ pi/3 "and" pi/6 \$.

10

Choice.A

Both cos\$π/3​\$ and sin\$π/6​\$ equal \$\sqrt(3)/2\$​​, and their product satisfies \$cos(x)sin(x) = \sqrt(3)/4\$​​. So, both values satisfy the equation

\$ pi/3, pi/6 \$

11

Choice.B

\$pi/2, 0\$ is not correct because these values do not satisfy the equation \$sin⁡(2x) + 2cos⁡(x)sin⁡(x) = \sqrt(3)\$

\$ pi/2, 0\$

12

Choice.C

The solution set from solving the equation is not fully represented by the intervals \$π/4\$ and \$π/2\$

\$ pi/4, pi/2 \$

13

Choice.D

This solution is incorrect because cos⁡(2π) and sin⁡(π) are both 0, so their product would be 0, not stem[\sqrt(3)/4]

\$ 2pi, pi \$

14

Answer

Option

A

15

Sumup

Can you summarize what you’ve understood in the above steps?


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