Question 1154334
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Since sin(a) = {{{3/5}}}, 


    cos(a) = {{{sqrt(1-sin^2(a))}}} = {{{sqrt(1-(3/5)^2)}}} = {{{sqrt(1-9/25)}}} = {{{sqrt(16/25)}}} = {{{4/5}}}.


Notice that since the angle "a" is in QI, cos(a) is positive; so, the sign of the square root is positive.


Next, since you know sin(a) and cos(a), you may calculate all other trigonometric functions  tan(a), cot(a), sec(a) and csc(a)


based on their definitions.
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In order for make writing easier, &nbsp;I replaced &nbsp;"theta" &nbsp;by &nbsp;"a" &nbsp;everywhere.