Below are common errors Please write a sentence explaining w

Below are common errors. Please write a sentence explaining what was done incorrectly. Then correct each one. a) sin(alpha + beta) = sin alpha + sin beta b) cos^-1 (x) = 1/cos(x) c) The phase shift (horizontal shift) of the graph y = sin (2x - pi) is pi.

Solution

a)

sine of compound angle not equal to sum of sines of individual angles

sin( +)=(sin cos) +(cos sin)

b)

trigonometric inverse function not equal to multiplicative inverse

there is no equation between cos^-1(x) and 1_/cosx

c)

the phase shift of the graph y=sin(2x -) is _/2

phase shift =-(-)_/2

phase shift =_/2