Step 1: Understanding the Concept:
We need to evaluate the given trigonometric expression by substituting the known values of \(\sin 90^\circ\) and \(\tan 45^\circ\).
Step 2: Key Formula or Approach:
We will use the standard trigonometric values:
\[ \sin 90^\circ = 1 \]
\[ \tan 45^\circ = 1 \]
Step 3: Detailed Explanation:
The expression is \(\sin^2 90^\circ - \tan^2 45^\circ\).
This can be written as \((\sin 90^\circ)^2 - (\tan 45^\circ)^2\).
Substitute the known values:
\[ = (1)^2 - (1)^2 \]
\[ = 1 - 1 \]
\[ = 0 \]
Step 4: Final Answer:
The value of the expression is 0.