Solve Equations with Inverse Tangent

  • 10th Grade
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| Questions: 20 | Updated: Dec 11, 2025
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1) Evaluate arctan(1) in radians.

Explanation

The question asks for the angle whose tangent is 1.

Since tan(π/4) = 1 and π/4 lies within the range (−π/2, π/2),

arctan(1) = π/4.

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About This Quiz
Solve Equations With Inverse Tangent - Quiz

Ready to explore how the arctangent (arctan) function links slopes, ratios, and angles. This quiz focuses on evaluating arctan values, identifying the correct principal range (–π/2 to π/2), and interpreting what each result represents on the unit circle. You will practice determining when tangent is positive or negative, finding corresponding... see moreangles in radians or degrees, and applying tan(arctan x) = x to verify results. By the end, you will build a strong conceptual understanding of inverse tangent relationships.
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2) Solve for x in the principal range: tan(x) = −√3.

Explanation

We know tan(π/3) = √3.

For a negative value, reflect across the x-axis → tan(−π/3) = −√3.

Since −π/3 is within the range (−π/2, π/2), x = −π/3.

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3) What is the range of y = arctan(x)?

Explanation

The arctangent function is restricted so it returns one unique angle.

That range is (−π/2, π/2), because tangent is undefined at ±π/2.

Hence, the correct range is (−π/2, π/2).

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4) Which value is NOT in the range of y = arctan(x)?

Explanation

The arctan range is (−π/2, π/2), and the endpoints are excluded.

Thus, 0, −π/3, and π/6 are valid, but π/2 is not in the range.

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5) Evaluate arctan(√3) in degrees.

Explanation

tan(60°) = √3.

Therefore, arctan(√3) = 60°, which lies in the valid range (−90°, 90°).

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6) If tan(θ) = 0.75 and θ = arctan(0.75), what is θ to the nearest tenth of a degree?

Explanation

We want the angle whose tangent is 0.75.

Since tan(36°) is slightly less than 0.75 and tan(37°) is slightly greater than 0.75, the correct angle is close to 37°.

Rounded to the nearest tenth of a degree, arctan(0.75) ≈ 36.9°.

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7) Evaluate tan(arctan(−2)).

Explanation

tan and arctan are inverse functions.

So tan(arctan(x)) = x for any real x.

Hence, tan(arctan(−2)) = −2.

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8) Solve 3tan(x) − √3 = 0 for the principal value of x.

Explanation

Start with the equation: 3tan(x) − √3 = 0

First, add √3 to both sides:

3tan(x) = √3

Then, divide both sides by 3:

tan(x) = √3 / 3

Then, we use the special-angle fact:

tan(π/6) = √3 / 3

So the principal-value angle satisfying tan(x) = √3/3 is:

x = π/6

This value lies in the arctan principal range (−π/2 to π/2).

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9) Evaluate arctan(0) in radians.

Explanation

tan(0) = 0.

So the angle whose tangent equals 0 is 0.

Therefore, arctan(0) = 0.

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10) A right triangle has opposite side 7 and adjacent side 7 relative to angle θ. Express θ using inverse tangent.

Explanation

Use the tangent ratio: tan(θ) = opposite / adjacent

First, substitute the values:

tan(θ) = 7 / 7

tan(θ) = 1

Then, to express θ, take the inverse tangent:

θ = arctan(1)

Since arctan(1) = 45°, this is the correct expression for θ.

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11) Evaluate arctan(−1) in radians.

Explanation

tan(−π/4) = −1.

Since −π/4 is within (−π/2, π/2), arctan(−1) = −π/4.

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12) Solve tan(x) = 0 for the principal value.

Explanation

tan(x) = 0 when x = 0, π, 2π, etc.

The principal value (in −π/2 to π/2) is 0.

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13) Solve for x (principal value): tan(x) = 5.

Explanation

arctan gives the unique angle between −π/2 and π/2 whose tangent is 5.

Thus, x = arctan(5).

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14) Evaluate arctan(4/3) to the nearest 0.01 radians.

Explanation

We want the angle whose tangent is 4/3 ≈ 1.33.

tan(0.79 rad) ≈ 1

tan(1.05 rad) ≈ 1.73

Since 1.33 lies between 1 and 1.73, the angle must be between 0.79 and 1.05 radians.

The closest value is about 0.93 radians.

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15) Which identity is always true for all real x?

Explanation

tan(arctan(x)) = x is always true because tan(arctan(x)) simply returns the original input x.

Whereas arctan(tan(x)) = x is not always true because arctan(tan(x)) only equals x when x is in the principal range (−π/2, π/2). Also, arctan(x) + arctan(1/x) = π/2 for all x is not always true; it holds only when x > 0.

and lastly arctan(x) = arcsin(x) is also false because arctan(x) and arcsin(x) are different functions with different domains and ranges.

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16) Solve for θ in (−π/2, π/2): 2tan(θ) = 2√3.

Explanation

Simplify: 2tan(θ) = 2√3 → tan(θ) = √3.

The angle whose tangent equals √3 is π/3.

Hence, θ = π/3.

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17) Evaluate arctan(−√3/3) in radians.

Explanation

tan(π/6) = √3/3.

Since the value is negative, the angle is −π/6 in the range (−π/2, π/2).

Thus, arctan(−√3/3) = −π/6.

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18) If arctan(a) = π/4, find a.

Explanation

Apply tangent to both sides: a = tan(π/4).

Since tan(π/4) = 1, a = 1.

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19) A ramp rises 18 inches over a horizontal run of 36 inches. Let θ be the angle of elevation. Which expression gives θ?

Explanation

tan(θ) = rise/run = 18/36 = 1/2.

So θ = arctan(18/36).

This gives the correct angle of elevation.

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20) Evaluate arctan(√3/3) in degrees.

Explanation

We use a known special-angle fact: tan(30°) = √3/3.

So the angle whose tangent equals √3/3 is 30°.

This value is also within the principal range of arctan, which is between −90° and 90°.

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Evaluate arctan(1) in radians.
Solve for x in the principal range: tan(x) = −√3.
What is the range of y = arctan(x)?
Which value is NOT in the range of y = arctan(x)?
Evaluate arctan(√3) in degrees.
If tan(θ) = 0.75 and θ = arctan(0.75), what is θ to...
Evaluate tan(arctan(−2)).
Solve 3tan(x) − √3 = 0 for the principal value of x.
Evaluate arctan(0) in radians.
A right triangle has opposite side 7 and adjacent side 7 relative to...
Evaluate arctan(−1) in radians.
Solve tan(x) = 0 for the principal value.
Solve for x (principal value): tan(x) = 5.
Evaluate arctan(4/3) to the nearest 0.01 radians.
Which identity is always true for all real x?
Solve for θ in (−π/2, π/2): 2tan(θ) = 2√3.
Evaluate arctan(−√3/3) in radians.
If arctan(a) = π/4, find a.
A ramp rises 18 inches over a horizontal run of 36 inches. Let θ be...
Evaluate arctan(√3/3) in degrees.
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