Answer:
120.51·cos(377t+4.80°)
Step-by-step explanation:
We can use the identity ...
sin(x) = cos(x -90°)
to transform the second waveform to ...
i₂(t) = 150cos(377t +50°)
Then ...
i(t) = i₁(t) -i₂(t) = 250cos(377t+30°) -150cos(377t+50°)
A suitable calculator finds the difference easily (see attached). It is approximately ...
i(t) = 120.51cos(377t+4.80°)
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The graph in the second attachment shows i(t) as calculated directly from the given sine/cosine functions (green) and using the result shown above (purple dotted). The two waveforms are identical.
