Questions: If sin θ=0.4, find the exact value of sin θ+cos (π/2-θ).
sin θ+cos (π/2-θ)=
(Type an integer or a decimal.)
Transcript text: If $\sin \theta=0.4$, find the exact value of $\sin \theta+\cos \left(\frac{\pi}{2}-\theta\right)$.
\[
\sin \theta+\cos \left(\frac{\pi}{2}-\theta\right)=
\]
$\square$
(Type an integer or a decimal.)
Solution
Solution Steps
To solve the given problem, we need to use the trigonometric identity that relates sine and cosine functions. Specifically, we use the identity \(\cos \left(\frac{\pi}{2} - \theta\right) = \sin \theta\). This allows us to simplify the expression \(\sin \theta + \cos \left(\frac{\pi}{2} - \theta\right)\).
Solution Approach
Recognize that \(\cos \left(\frac{\pi}{2} - \theta\right) = \sin \theta\).
Substitute \(\cos \left(\frac{\pi}{2} - \theta\right)\) with \(\sin \theta\).
Simplify the expression to find the exact value.
Step 1: Given Information
We are given that \( \sin \theta = 0.4 \).
Step 2: Use Trigonometric Identity
We apply the identity \( \cos \left(\frac{\pi}{2} - \theta\right) = \sin \theta \). Therefore, we can rewrite the expression: