Use the following three identities to evaluate sin 10x cos 7x dx. sin sx cos tx = sin sx sin tx = cos sx cos tx = sin 10x cos 7x dx = [sin (s+t)x+ sin (s-t)x] [cos (s+t)x − cos (s − t)x] [cos(s+t)x+ cos (s-t)x]

2 X ( 큰f 높다. 1- cos 2Tx ) dx

Use the cofunction identities to select the correct answer which fills in the blank. cos(10x) = sin_ O cos(10x) = sin(180° + 10x) O cos(10x) = sin(180° – 10x) O cos(10x) = sin(90° + 10x) O cos(10x) = sin(10x – 90°) O cos(10x) sin(90° – 10x)

Multiply 1 + cos(4x) and use trig identity sin x + cos x = 1 for any x