Practicing Success
If sin A = $\frac{4}{5}$ and sin B = $\frac{15}{17}$, what is the value of sin(A - B) ? |
$-\frac{32}{45}$ $-\frac{13}{85}$ $\frac{13}{85}$ $\frac{32}{45}$ |
$-\frac{13}{85}$ |
sinA = \(\frac{4}{5}\) sinB = \(\frac{15}{17}\) By using pythagoras theorem , By using pythagoras theorem , P2 + B2 = H2 P2 + B2 = H2 42 + B2 = 52 152 + B2 = 172 B = 3 B = 8 cos A = \(\frac{3}{5}\) cos B = \(\frac{8}{17}\) sin ( A - B ) = sinA cosB - cosA sinB = \(\frac{4}{5}\) × \(\frac{8}{17}\) - \(\frac{3}{5}\) × \(\frac{15}{17}\) = \(\frac{32}{85}\) - \(\frac{45}{85}\) = - \(\frac{13}{85}\)
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