Question 1041887
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2) If tan θ = 5/4, calculate the value of cos θ.
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Use this trigonometry identity: {{{cos^2(theta)}}} = {{{1/(1 + tan^2(theta))}}}.

Then you have {{{cos^2(theta)}}} = {{{1/(1 + (5/4)^2)}}} = {{{1/(1 + 25/16)}}} = {{{16/(25 + 16)}}} = {{{16/41}}}.

Hence, {{{cos(theta)}}} = +/- {{{4/sqrt(41)}}}.
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