We read your photo as:

Given that SinA = 3/5 for 0° < A < 90° and SinB = sqrt(3)/3 for 180° < B < 270°, find the exact value of tan(A - B).

Mathematics

ScanSolve AI Answer

Answer

tan⁡(A−B)=36−25223\tan(A - B) = \frac{36 - 25\sqrt{2}}{23}

Step-by-step solution

3 steps
  1. Find tan⁡A\tan A.

    Given sin⁡A=35\sin A = \frac{3}{5} for 0∘<A<90∘0^\circ < A < 90^\circ (Quadrant I). In Quadrant I, cos⁡A\cos A is positive.
    Using the Pythagorean identity sin⁡2A+cos⁡2A=1\sin^2 A + \cos^2 A = 1:

    cos⁡2A=1−(35)2=1−925=1625\cos^2 A = 1 - \left(\frac{3}{5}\right)^2 = 1 - \frac{9}{25} = \frac{16}{25} cos⁡A=1625=45\cos A = \sqrt{\frac{16}{25}} = \frac{4}{5}

    Now, calculate tan⁡A\tan A:

    tan⁡A=sin⁡Acos⁡A=3/54/5=34\tan A = \frac{\sin A}{\cos A} = \frac{3/5}{4/5} = \frac{3}{4}
  2. Find tan⁡B\tan B.

    Given sin⁡B=33\sin B = \frac{\sqrt{3}}{3} for 180∘<B<270∘180^\circ < B < 270^\circ.
    Contradiction: In the third quadrant (180∘<B<270∘180^\circ < B < 270^\circ), the sine function is negative. However, the given value sin⁡B=33\sin B = \frac{\sqrt{3}}{3} is positive. This means there is no angle BB that satisfies both conditions simultaneously.
    Assumption: To proceed with the problem, we will assume there is a typo in the question and that sin⁡B\sin B was intended to be negative, i.e., sin⁡B=−33\sin B = -\frac{\sqrt{3}}{3}, which is consistent with BB being in the third quadrant.
    With sin⁡B=−33\sin B = -\frac{\sqrt{3}}{3} and BB in Quadrant III, cos⁡B\cos B is negative.
    Using the Pythagorean identity sin⁡2B+cos⁡2B=1\sin^2 B + \cos^2 B = 1:

    cos⁡2B=1−(−33)2=1−39=1−13=23\cos^2 B = 1 - \left(-\frac{\sqrt{3}}{3}\right)^2 = 1 - \frac{3}{9} = 1 - \frac{1}{3} = \frac{2}{3} cos⁡B=−23=−23=−63\cos B = -\sqrt{\frac{2}{3}} = -\frac{\sqrt{2}}{\sqrt{3}} = -\frac{\sqrt{6}}{3}

    Now, calculate tan⁡B\tan B:

    tan⁡B=sin⁡Bcos⁡B=−3/3−6/3=36=12=22\tan B = \frac{\sin B}{\cos B} = \frac{-\sqrt{3}/3}{-\sqrt{6}/3} = \frac{\sqrt{3}}{\sqrt{6}} = \frac{1}{\sqrt{2}} = \frac{\sqrt{2}}{2}
  3. Use the tangent subtraction formula.

    The formula for tan⁡(A−B)\tan(A - B) is:

    tan⁡(A−B)=tan⁡A−tan⁡B1+tan⁡Atan⁡B\tan(A - B) = \frac{\tan A - \tan B}{1 + \tan A \tan B}

    Substitute the values tan⁡A=34\tan A = \frac{3}{4} and tan⁡B=22\tan B = \frac{\sqrt{2}}{2}:

    tan⁡(A−B)=34−221+(34)(22)\tan(A - B) = \frac{\frac{3}{4} - \frac{\sqrt{2}}{2}}{1 + \left(\frac{3}{4}\right)\left(\frac{\sqrt{2}}{2}\right)} tan⁡(A−B)=34−2241+328\tan(A - B) = \frac{\frac{3}{4} - \frac{2\sqrt{2}}{4}}{1 + \frac{3\sqrt{2}}{8}} tan⁡(A−B)=3−2248+328\tan(A - B) = \frac{\frac{3 - 2\sqrt{2}}{4}}{\frac{8 + 3\sqrt{2}}{8}} tan⁡(A−B)=3−224×88+32\tan(A - B) = \frac{3 - 2\sqrt{2}}{4} \times \frac{8}{8 + 3\sqrt{2}} tan⁡(A−B)=2(3−22)8+32=6−428+32\tan(A - B) = \frac{2(3 - 2\sqrt{2})}{8 + 3\sqrt{2}} = \frac{6 - 4\sqrt{2}}{8 + 3\sqrt{2}}

    To rationalize the denominator, multiply the numerator and denominator by the conjugate 8−328 - 3\sqrt{2}:

    tan⁡(A−B)=6−428+32×8−328−32\tan(A - B) = \frac{6 - 4\sqrt{2}}{8 + 3\sqrt{2}} \times \frac{8 - 3\sqrt{2}}{8 - 3\sqrt{2}} tan⁡(A−B)=(6)(8)+(6)(−32)+(−42)(8)+(−42)(−32)82−(32)2\tan(A - B) = \frac{(6)(8) + (6)(-3\sqrt{2}) + (-4\sqrt{2})(8) + (-4\sqrt{2})(-3\sqrt{2})}{8^2 - (3\sqrt{2})^2} tan⁡(A−B)=48−182−322+12(2)64−9(2)\tan(A - B) = \frac{48 - 18\sqrt{2} - 32\sqrt{2} + 12(2)}{64 - 9(2)} tan⁡(A−B)=48−502+2464−18\tan(A - B) = \frac{48 - 50\sqrt{2} + 24}{64 - 18} tan⁡(A−B)=72−50246\tan(A - B) = \frac{72 - 50\sqrt{2}}{46} tan⁡(A−B)=2(36−252)2(23)\tan(A - B) = \frac{2(36 - 25\sqrt{2})}{2(23)} tan⁡(A−B)=36−25223\tan(A - B) = \boxed{\frac{36 - 25\sqrt{2}}{23}}
Was this helpful?

Still stuck on this one?

Ask a follow-up, and the answer starts from this question.

Got a different question?Ask your own question