Question 1170371
if given {{{tan(theta)=3/4 }}}and theta is in quadrant {{{IV}}},


{{{cos(2theta) = (1 -tan(theta)^2)/(1 +tan(theta)^2)}}}

 {{{ cos(2theta) = (1 -(-3/4)^2)/(1 +(-3/4)^2)}}}

  {{{ cos(2theta) = ((16-9)/16)/((16+9)/16)}}}

  {{{ cos(2theta) = 7/25}}}


answer: d. {{{7/25}}}


and

 {{{ tan(2theta) = (2tan(theta))/(1 -tan(theta)^2)}}}

 {{{ tan(2theta)= (2(3/4))/(1-(3/4)^2)}}}

 {{{ tan(2theta)= (6/4)/(7/16)}}}

  {{{tan(2theta) = 24/7}}}

answer: a.{{{24/7}}}