calculate-time-from-the-equation-with-sin-and-cos

[ncchieh]

Va =(-3sin t) i +(4cos t) j
Vb =(3cos t) i + (-4sin t) j

-3 sint = -(3 cost) .......................(1)
4 cost = -(-4 sint) ........................(2)

from (1)
(sin/cos) t = 1
tan t = 1
t = 45

from (2)
(sin/cos) t = 1
tan t = 1
t = 45

is this correct?
or I did something wrong

 

[Deleted member 4993]

View attachment 13271

Va =(-3sin t) i +(4cos t) j
Vb =(3cos t) i + (-4sin t) j

-3 sint = -(3 cost) .......................(1)
4 cost = -(-4 sint) ........................(2)

from (1)
(sin/cos) t = 1
tan t = 1
t = 45

from (2)
(sin/cos) t = 1
tan t = 1
t = 45

is this correct?
or I did something wrong

This is a duplicate thread.

https://www.freemathhelp.com/forum/...equation-with-sin-and-cos.117488/#post-462997

 

[HallsofIvy]

"-3 sint = -(3 cost) .......................(1)
4 cost = -(-4 sint) ........................(2)"
You were asked to determine when the two particles were first moving in opposite directions. Solving these two equations would give t when the two particles are moving in opposite directions at the same speed.