Q. If tanA=3512 and cosB=1715 and angles A and B are in Quadrant I, find the value of tan(A−B).Answer:
Use tan(A−B) Formula: Use the formula for tan(A−B), which is tan(A−B)=1+tanA⋅tanBtanA−tanB. We are given tanA=3512. We need to find tanB using the given cosB=1715.
Find tanB: Since cosB=1715, we can find sinB using the Pythagorean identity sin2B+cos2B=1.sin2B=1−cos2Bsin2B=1−(1715)2sin2B=1−289225sin2B=289289−225sin2B=28964sinB=28964cosB=17150, since cosB=17151 is in Quadrant I, sinB is positive.
Calculate tanB: Now we can find tanB using the ratio tanB=cosBsinB.tanB=178/1715tanB=178⋅1517tanB=158
Substitute tan Values: Substitute the values of tanA and tanB into the tan(A−B) formula.tan(A−B)=1+tanA⋅tanBtanA−tanBtan(A−B)=1+(3512)⋅(158)(3512)−(158)
Simplify Numerator/Denominator: Simplify the numerator and the denominator separately.Numerator: (3512)−(158)=(35×312×3−8×7)Numerator: (10536−56)=105−20=21−4Denominator: 1+(3512)×(158)=1+((35×15)96)Denominator: 1+(52596)=(525525+96)=525621=175207
Divide to Find tan(A−B): Now divide the numerator by the denominator to find tan(A−B).tan(A−B)=21−4/175207tan(A−B)=21−4⋅207175
Final Simplification: Simplify the expression by canceling out common factors.tan(A−B)=(−4×175)/(21×207)tan(A−B)=(−700)/(4347)tan(A−B)=−100/621
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