Question

Which of the following is not = to 0
a. cos(pi/2)
b. tan(0)
c. cos(pi/4)-sin(pi/4)
d. sin^-1(pi)
e. cos^-1(1)

I know the answer is either d or e

Answer 1

sin pi is 0
cos 1 is (pi/2))

Answer 2

sorry that was not what they wanted...

cos(?) = 1

sin(?) = pi

Answer 3

2pi
0

Answer 4

no sin(0) = 0

Answer 5

cos(0) = 1

Answer 6

answer then must be D

Answer 7

but it's inverse sin and inverse cos the inverse is confusing to me

Answer 8

ok the output of the inverse is the angle

\[\sin \theta = x \rightarrow \theta = \sin^{-1} x\]

so when they ask about an inverse, think sin of what angle will give me that number

example
\[\cos^{-1} \frac{\sqrt{2}}{2}\]
rewrite it as
\[\cos \theta = \frac{\sqrt{2}}{2}\]
then from the unit circle you know the angle must be pi/4
\[\cos^{-1} \frac{\sqrt{2}}{2} = \frac{\pi}{4}\]

Answer 9

so because it's cos^-1(1) the angle is 0 therefore cos^-1(1)=0?

Answer 10

correct

Answer 11

thanks!

Answer 12

yw :)