Question

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.

Thanks

Answer 1

PIa = pi*a

PI/2 = pi/2

Answer 2

E=-20cos(pi*a/4)

Answer 3

Any chance you could show a bit of work? Thanks.

Answer 4

sin(x-y)=sin(x)cos(y)-sin(y)cos(x)
Let y=pi/2
sin(x-pi/2)=sin(x)*0-1*cos(x)=-cos(x)