If = 3/4 , find the value of cos2 ?

Answer: Option C

$$\begin{array}{rl}& \tan \theta =\frac{3}{4}\\ & \text{cos2}\theta =\frac{1-\text{ta}{\text{n}}^2\theta }{1+\text{ta}{\text{n}}^2\theta }\\ & =\frac{1-\frac{9}{16}}{1+\frac{9}{16}}\\ & =\frac{\frac{7}{16}}{\frac{25}{16}}\\ & \text{cos2}\theta =\frac{7}{25}\end{array}$$