Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

What is the exact value of tan(19π12)\tan\left(\frac{19\pi}{12}\right)?

Full solution

Q. What is the exact value of tan(19π12)\tan\left(\frac{19\pi}{12}\right)?
  1. Express as Sum/Difference: To find the exact value of tan(19π12)\tan\left(\frac{19\pi}{12}\right), we can express 19π12\frac{19\pi}{12} as a sum or difference of angles for which we know the exact values of the trigonometric functions. The angles we commonly use are multiples of π6\frac{\pi}{6}, π4\frac{\pi}{4}, and π3\frac{\pi}{3} because their trigonometric values are well known and can be easily calculated.
  2. Apply Angle Sum Identity: We can express (19π)/12(19\pi)/12 as the sum of (16π)/12(16\pi)/12 and (3π)/12(3\pi)/12, which simplifies to (4π)/3+π/4(4\pi)/3 + \pi/4. These two angles are more familiar, and we can use the angle sum identity for tangent to find the exact value of tan((19π)/12)\tan((19\pi)/12).
  3. Calculate Exact Values: The angle sum identity for tangent is tan(A+B)=tan(A)+tan(B)1tan(A)tan(B)\tan(A + B) = \frac{\tan(A) + \tan(B)}{1 - \tan(A)\tan(B)}. We will use A=4π3A = \frac{4\pi}{3} and B=π4B = \frac{\pi}{4} for our calculation.
  4. Plug into Identity: First, we find the exact values of tan(4π3)\tan(\frac{4\pi}{3}) and tan(π4)\tan(\frac{\pi}{4}). tan(4π3)\tan(\frac{4\pi}{3}) is equivalent to tan(ππ3)\tan(\pi - \frac{\pi}{3}), which is the same as tan(π3)-\tan(\frac{\pi}{3}) because tangent is negative in the third quadrant. The exact value of tan(π3)\tan(\frac{\pi}{3}) is 3\sqrt{3}, so tan(4π3)=3\tan(\frac{4\pi}{3}) = -\sqrt{3}. tan(π4)\tan(\frac{\pi}{4}) is 11 because it's the tangent of a tan(π4)\tan(\frac{\pi}{4})00-degree angle.
  5. Simplify Expression: Now we can plug these values into the angle sum identity: tan(19π12)=tan(4π3+π4)=3+11(31)\tan\left(\frac{19\pi}{12}\right) = \tan\left(\frac{4\pi}{3} + \frac{\pi}{4}\right) = \frac{-\sqrt{3} + 1}{1 - (-\sqrt{3} \cdot 1)}.
  6. Rationalize Denominator: Simplifying the expression, we get tan(19π12)=3+11+3\tan\left(\frac{19\pi}{12}\right) = \frac{-\sqrt{3} + 1}{1 + \sqrt{3}}. To rationalize the denominator, we multiply the numerator and the denominator by the conjugate of the denominator, which is (13)(1 - \sqrt{3}).
  7. Expand Numerator: Multiplying the numerator and denominator by the conjugate, we get: tan(19π12)=[3+1][13][1+3][13]\tan\left(\frac{19\pi}{12}\right) = \frac{[-\sqrt{3} + 1][1 - \sqrt{3}]}{[1 + \sqrt{3}][1 - \sqrt{3}]}.
  8. Expand Denominator: Expanding the numerator, we get: (3+1)(13)=33+31(-\sqrt{3} + 1)(1 - \sqrt{3}) = -3 - \sqrt{3} + \sqrt{3} - 1. The 3\sqrt{3} terms cancel out, leaving us with 31-3 - 1.
  9. Final Simplification: Expanding the denominator, we get: (1+3)(13)=13(1 + \sqrt{3})(1 - \sqrt{3}) = 1 - 3, which simplifies to 2-2.
  10. Final Simplification: Expanding the denominator, we get: (1+3)(13)=13(1 + \sqrt{3})(1 - \sqrt{3}) = 1 - 3, which simplifies to 2-2.Now we have tan(19π12)=42\tan\left(\frac{19\pi}{12}\right) = \frac{-4}{-2}, which simplifies to 22.

More problems from Find derivatives of other trigonometric functions