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If 
cos A=(12)/(37) and 
sin B=(3)/(5) and angles A and B are in Quadrant I, find the value of 
tan(A-B).
Answer:

If cosA=1237 \cos A=\frac{12}{37} and sinB=35 \sin B=\frac{3}{5} and angles A and B are in Quadrant I, find the value of tan(AB) \tan (A-B) .\newlineAnswer:

Full solution

Q. If cosA=1237 \cos A=\frac{12}{37} and sinB=35 \sin B=\frac{3}{5} and angles A and B are in Quadrant I, find the value of tan(AB) \tan (A-B) .\newlineAnswer:
  1. Find sinA\sin A: We know that cosA=1237\cos A = \frac{12}{37}. Since AA is in Quadrant I, where both sine and cosine are positive, we can find sinA\sin A using the Pythagorean identity sin2A+cos2A=1\sin^2 A + \cos^2 A = 1. First, calculate sin2A\sin^2 A: sin2A=1cos2A\sin^2 A = 1 - \cos^2 A sin2A=1(1237)2\sin^2 A = 1 - \left(\frac{12}{37}\right)^2 sin2A=11441369\sin^2 A = 1 - \frac{144}{1369} sin2A=136913691441369\sin^2 A = \frac{1369}{1369} - \frac{144}{1369} cosA=1237\cos A = \frac{12}{37}00 Now, take the square root to find sinA\sin A: cosA=1237\cos A = \frac{12}{37}22 cosA=1237\cos A = \frac{12}{37}33
  2. Find cosB\cos B: We also know that sinB=35\sin B = \frac{3}{5}. Since B is in Quadrant I, where both sine and cosine are positive, we can find cosB\cos B using the Pythagorean identity sin2B+cos2B=1\sin^2 B + \cos^2 B = 1.\newlineFirst, calculate cos2B\cos^2 B:\newlinecos2B=1sin2B\cos^2 B = 1 - \sin^2 B\newlinecos2B=1(35)2\cos^2 B = 1 - \left(\frac{3}{5}\right)^2\newlinecos2B=1925\cos^2 B = 1 - \frac{9}{25}\newlinecos2B=2525925\cos^2 B = \frac{25}{25} - \frac{9}{25}\newlinecos2B=1625\cos^2 B = \frac{16}{25}\newlineNow, take the square root to find cosB\cos B:\newlinesinB=35\sin B = \frac{3}{5}11\newlinesinB=35\sin B = \frac{3}{5}22
  3. Calculate tan(AB)\tan(A-B): Now we need to find tan(AB)\tan(A-B). We can use the formula for the tangent of the difference of two angles:\newlinetan(AB)=tanAtanB1+tanAtanB\tan(A-B) = \frac{\tan A - \tan B}{1 + \tan A \cdot \tan B}\newlineWe already have sinA\sin A and cosA\cos A, and sinB\sin B and cosB\cos B, so we can find tanA\tan A and tanB\tan B:\newlinetanA=sinAcosA\tan A = \frac{\sin A}{\cos A}\newlinetanA=35/3712/37\tan A = \frac{35/37}{12/37}\newlinetanA=3512\tan A = \frac{35}{12}\newlinetanB=sinBcosB\tan B = \frac{\sin B}{\cos B}\newlinetanB=3/54/5\tan B = \frac{3/5}{4/5}\newlinetanB=34\tan B = \frac{3}{4}
  4. Calculate tan(AB)\tan(A-B): Now we need to find tan(AB)\tan(A-B). We can use the formula for the tangent of the difference of two angles:\newlinetan(AB)=tanAtanB1+tanAtanB\tan(A-B) = \frac{\tan A - \tan B}{1 + \tan A \cdot \tan B}\newlineWe already have sinA\sin A and cosA\cos A, and sinB\sin B and cosB\cos B, so we can find tanA\tan A and tanB\tan B:\newlinetanA=sinAcosA\tan A = \frac{\sin A}{\cos A}\newlinetanA=35/3712/37\tan A = \frac{35/37}{12/37}\newlinetanA=3512\tan A = \frac{35}{12}\newlinetanB=sinBcosB\tan B = \frac{\sin B}{\cos B}\newlinetanB=3/54/5\tan B = \frac{3/5}{4/5}\newlinetanB=34\tan B = \frac{3}{4}Substitute tanA\tan A and tanB\tan B into the formula for tan(AB)\tan(A-B):\newlinetan(AB)=tanAtanB1+tanAtanB\tan(A-B) = \frac{\tan A - \tan B}{1 + \tan A \cdot \tan B}\newlinetan(AB)=3512341+(3512)(34)\tan(A-B) = \frac{\frac{35}{12} - \frac{3}{4}}{1 + \left(\frac{35}{12}\right) \cdot \left(\frac{3}{4}\right)}\newlineTo subtract the fractions, find a common denominator:\newlinetan(AB)=35129121+(3512)(34)\tan(A-B) = \frac{\frac{35}{12} - \frac{9}{12}}{1 + \left(\frac{35}{12}\right) \cdot \left(\frac{3}{4}\right)}\newlinetanA=sinAcosA\tan A = \frac{\sin A}{\cos A}00\newlineNow simplify the fractions:\newlinetanA=sinAcosA\tan A = \frac{\sin A}{\cos A}11\newlinetanA=sinAcosA\tan A = \frac{\sin A}{\cos A}22\newlinetanA=sinAcosA\tan A = \frac{\sin A}{\cos A}33\newlineNow multiply by the reciprocal of the denominator:\newlinetanA=sinAcosA\tan A = \frac{\sin A}{\cos A}44\newlineSimplify the fraction by canceling common factors:\newlinetanA=sinAcosA\tan A = \frac{\sin A}{\cos A}55\newlinetanA=sinAcosA\tan A = \frac{\sin A}{\cos A}66\newlinetanA=sinAcosA\tan A = \frac{\sin A}{\cos A}77\newlineFinally, simplify the fraction:\newlinetanA=sinAcosA\tan A = \frac{\sin A}{\cos A}88

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