196k views
5 votes
Trigonometry Question

Trigonometry Question-example-1
User Cun
by
8.2k points

1 Answer

1 vote

Answer: To show that the equation "3sin () tan () = 5cos () - 2" is equivalent to the equation "(4 cos() - 3)(2 cos () + 1) = 0", we need to simplify the first equation and check if it has the same solutions as the second equation.

Starting with the first equation:

3sin () tan () = 5cos () - 2

Using the identity tan () = sin () / cos (), we can write:

3sin () (sin () / cos ()) = 5cos () - 2

Multiplying both sides by cos (), we get:

3sin^2 () = (5cos () - 2)cos ()

Using the identity sin^2 () + cos^2 () = 1 and rearranging, we get:

3(1 - cos^2 ()) = 5cos^2 () - 2cos ()

Expanding and rearranging, we get:

5cos^2 () - 2cos () - 3 + 3cos^2 () = 0

Simplifying, we get:

8cos^2 () - 2cos () - 3 = 0

Now, we can use the quadratic formula to solve for cos ():

cos () = [2 ± sqrt(2^2 - 4(8)(-3))]/(2(8))

cos () = [2 ± sqrt(100)]/16

cos () = (1/4) or (-3/8)

Substituting these values back into the original equation, we can verify that they satisfy the equation.

Now, let's consider the second equation:

(4 cos() - 3)(2 cos () + 1) = 0

This equation is satisfied when either 4cos() - 3 = 0 or 2cos() + 1 = 0.

Solving for cos() in the first equation, we get:

4cos() - 3 = 0

cos() = 3/4

Substituting this value back into the original equation, we can verify that it satisfies the equation.

Solving for cos() in the second equation, we get:

2cos() + 1 = 0

cos() = -1/2

Substituting this value back into the original equation, we can also verify that it satisfies the equation.

Therefore, we have shown that the equation "3sin () tan () = 5cos () - 2" is equivalent to the equation "(4 cos() - 3)(2 cos () + 1) = 0".

User ZoomIn
by
8.4k points

No related questions found