Mathematics

Problem

Let

\theta

be an acute angle such that

\tan\theta = p\,(p>0)

. Which of the following expresses

\cos\theta

in terms of

p

? a)

\dfrac{p}{\sqrt{1+p^{2}}}

\dfrac{1}{1+p^{2}}

\dfrac{1}{\sqrt{1+p^{2}}}

\dfrac{1}{p}