Q. Given that tanx=23 and cosy=376, and that angles x and y are both in Quadrant I, find the exact value of sin(x−y), in simplest radical form.Answer:
Given values: We are given tanx=23 and cosy=376. Since tanx=cosxsinx, we can create a right triangle with opposite side 3, adjacent side 2, and hypotenuse 32+22=13 to find sinx and cosx.
Finding sinx: Using the Pythagorean theorem, sinx=hypotenuseopposite=133. We rationalize the denominator to get sinx=13313.
Finding siny: We are also given cosy=376. To find siny, we use the Pythagorean identity sin2y+cos2y=1. Substituting cosy, we get sin2y+(376)2=1.
Using sine difference formula: Solving for siny, we have sin2y=1−3736. This simplifies to sin2y=3737−3736=371. Taking the square root, siny=371=371, and we rationalize the denominator to get siny=3737.
Simplify the expression: Now we use the sine difference formula: sin(x−y)=sinx⋅cosy−cosx⋅siny. We substitute the values we found: sin(x−y)=(13313)⋅(376)−(132)⋅(3737).
Further simplification: Simplify the expression: sin(x−y)=37/131813−13/37237. This simplifies to sin(x−y)=13⋅371813⋅37−37⋅13237⋅13.
Combine the terms: Further simplification gives us sin(x−y)=13⋅3718481−13⋅372481. Since the denominators are the same, we can combine the terms.
Final simplification: Combining the terms, we get sin(x−y)=13⋅3718481−2481. This simplifies to sin(x−y)=13⋅3716481.
Final simplification: Combining the terms, we get sin(x−y)=13⋅3718481−2481. This simplifies to sin(x−y)=13⋅3716481.Finally, we simplify the expression by dividing both numerator and denominator by their greatest common divisor, which is 1 in this case. So, the expression is already in its simplest form: sin(x−y)=13⋅3716481.
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