Question 1033489
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If cos theta equals -4/9 with theta in quadrant 2, find sin theta.
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{{{sin(theta)}}} = +{{{sqrt(1 - cos^2(theta))}}} = {{{sqrt(1-(-4/9)^2)}}} = {{{sqrt(1 - 16/81)}}} = {{{sqrt((81-16)/81)}}} = {{{sqrt(65/81)}}} = {{{sqrt(65)/9}}}.


The sign is "+" since {{{theta}}} is in quadrant 2, where sine is positive.