Question

solving trig equations:
1. cos θ = 1/4
2. sin θ = -0.4
3. sin θ = -0.15
4. tan θ = -1

Answer 1

Do you want to show the exact solution or will a decimal approximation from a calculator suffice?

Answer 2

For all of these, the unknown to solve for is Θ. It is found by taking the inverse trig function of the given ratio.

Answer 3

exact solution is best. I get that its the inverse but I have to show it in general form like this: \[\pi/2 +2k \pi \]

Answer 4

I see. Ok, that's fine.
#4. is the easiest to see right away. The tangent of an angle is equal to the slope of the line. What angle is formed by a line with a slope of -1?

Answer 5

\[\theta =\cos^{-1} (1/4)\]

Answer 6

\[\theta=\sin^{-1} (-0.4)\]

Answer 7

\[\theta=\sin^{-1} (-0.15)\]

Answer 8

\[\theta= \tan^{-1} (-1)\]

Answer 9

solve them by your calculator to find answers... if not then tell me i'll send you the answers too..

Answer 10

I understand how to do that, but I don't get how to have them in \[\pi \] form?

Answer 11

multiply answers by (pi/180) you'll get what you need... then answers will be in radians..

Answer 12

look angle in "pi" means angle in radian not in degree... so you can convert the degree angles into radians by multiplying it by (pi/180)..
got it now??

Answer 13

yes thanks

Answer 14

Only problem with that is if you use a calculator to evaluate, say, arccos(1/4) = 1.318116... radians.
It is difficult to see how many multiples or parts of π that is.

Answer 15

I get what your saying and thats why its not accepting the answers for my homework