Amin

1. Community
2. Study Group
3. Trigonometry Identities

cos(x) = 1 / sec(x) cos(x) = 1 / sqrt[1 + tan^2(x)] cos(x) = 1 / sqrt[1 + 1/cot^2(x)] cos(x) = 1 / sqrt[(cot^2(x)/cot^2(x) + 1/cot^2(x)] cos(x) = 1 / sqrt[(cot^2(x) + 1) / cot^2(x)] cos(x) = 1 / [...

1. Community
2. Study Group
3. Establishing Trig identities

Here's what I was able to get:  cos@tan@ + cos@cot@ = csc@ cos@(sin@/cos@) + cos@(cos@/sin@) = csc@ sin@ + cos^2@/sin@ = csc@ sin@(sin@ + cos^2@/sin@) = sin@csc@ sin^2@ + cos^2@ = sin@(1/sin@) 1 =...

1. Community
2. Study Group
3. Using addition/subtraction identities to solve an angle

Hi e.davis.brown.  Did you remember to use the appropriate sign when evaluating the angle sum identity (eg, sin300 is negative, not positive)? Here's what I was able to get: cos(A+B) = cosAcosB - ...

1. Community
2. Study Group
3. is time travel possible

It is possible, as long as you're going to the future.  Hawking was describing the phenomenon of time dilation.  If you hopped into a spaceship and left Earth, travelling very close to the speed of...