If \[{{\varphi }_{1}}\] and \[{{\varphi }_{2}}\] be the angles of dip observed in two vertical planes at right angles to each other and f be the true angle of dip, then

\[{{\cos }^{2}}\varphi ={{\cos }^{2}}{{\varphi }_{1}}+{{\cos }^{2}}{{\varphi }_{2}}\]

\[{{\sec }^{2}}\varphi ={{\sec }^{2}}{{\varphi }_{1}}+{{\sec }^{2}}{{\varphi }_{2}}\]

\[{{\tan }^{2}}\varphi ={{\tan }^{2}}{{\varphi }_{1}}+{{\tan }^{2}}{{\varphi }_{2}}\]

\[{{\cot }^{2}}\varphi ={{\cot }^{2}}{{\varphi }_{1}}+{{\cot }^{2}}{{\varphi }_{2}}\]

If \[{{\varphi }_{1}}\] and \[{{\varphi }_{2}}\] be the angles of dip

1.	If \[{{\varphi }_{1}}\] and \[{{\varphi }_{2}}\] be the angles of dip observed in two vertical planes at right angles to each other and f be the true angle of dip, then
A.	\[{{\cos }^{2}}\varphi ={{\cos }^{2}}{{\varphi }_{1}}+{{\cos }^{2}}{{\varphi }_{2}}\]
B.	\[{{\sec }^{2}}\varphi ={{\sec }^{2}}{{\varphi }_{1}}+{{\sec }^{2}}{{\varphi }_{2}}\]
C.	\[{{\tan }^{2}}\varphi ={{\tan }^{2}}{{\varphi }_{1}}+{{\tan }^{2}}{{\varphi }_{2}}\]
D.	\[{{\cot }^{2}}\varphi ={{\cot }^{2}}{{\varphi }_{1}}+{{\cot }^{2}}{{\varphi }_{2}}\]
Answer» E.