Questions: Simplify: 10 sin (-t) csc (-t)+6 cos (-t) sec (-t)
A) 16
B) 2
C) 4
D) -16
E) -4
F) None of these
Transcript text: 9. Simplify: $10 \sin (-t) \csc (-t)+6 \cos (-t) \sec (-t)$
A) 16
B) 2
C) 4
D) -16
E) -4
F) None of these
Solution
Solution Steps
To simplify the given expression, we need to use the properties of trigonometric functions. Specifically, we will use the fact that \(\sin(-t) = -\sin(t)\) and \(\cos(-t) = \cos(t)\). Additionally, we will use the identities \(\csc(t) = \frac{1}{\sin(t)}\) and \(\sec(t) = \frac{1}{\cos(t)}\).
Solution Approach
Substitute \(\sin(-t)\) and \(\cos(-t)\) with their equivalent expressions.
Simplify the trigonometric functions using their reciprocal identities.
Combine and simplify the resulting expression.
Step 1: Substitute Trigonometric Identities
We start by substituting \(\sin(-t)\) and \(\cos(-t)\) with their equivalent expressions:
\[
\sin(-t) = -\sin(t) \quad \text{and} \quad \cos(-t) = \cos(t)
\]
Step 2: Apply Reciprocal Identities
Next, we use the reciprocal identities:
\[
\csc(t) = \frac{1}{\sin(t)} \quad \text{and} \quad \sec(t) = \frac{1}{\cos(t)}
\]
Step 3: Simplify the Expression
Substituting these into the original expression:
\[
10 \sin(-t) \csc(-t) + 6 \cos(-t) \sec(-t)
\]
becomes:
\[
10 (-\sin(t)) \csc(t) + 6 \cos(t) \sec(t)
\]
which simplifies to:
\[
10 (-\sin(t)) \left(\frac{1}{\sin(t)}\right) + 6 \cos(t) \left(\frac{1}{\cos(t)}\right)
\]
This further simplifies to:
\[
10 (-1) + 6 (1) = -10 + 6 = -4
\]
Final Answer
The simplified expression is:
\[
\boxed{-4}
\]
Thus, the answer is E.