posted by Blake on .
A coil of wire rotating in a magnetic field induces a coltage E=20sin((PIa/4) - (PI/2)). Use an identity to express this in terms of cos(PIa/4).
Types of Identities:
Double Angle, Half Angle, Sum and Difference of Sine, Cosine, and Tangent, Pythagorean, Reciprocal, Quotient.