Trig Transformations
1. Problem a: Find the new coordinates of point P after the transformation from $y=\tan x$ to $y=\tan 5x$.
- Given original point $P=(45^\circ,1)$ on $y = \tan x$.
- New function is $y = \tan 5x$.
- The transformation compresses the graph horizontally by a factor of $1/5$.
- The new $x$-coordinate is found by solving $5x = 45^\circ \Rightarrow x = \dfrac{45^\circ}{5} = 9^\circ$.
- The $y$-coordinate remains the same for the corresponding $x$ in the transformed graph: $y = \tan(5 \times 9^\circ) = \tan 45^\circ = 1$.
So the new coordinates are $P' = (9^\circ, 1)$.
2. Problem b: Find the new coordinates of point Q after the transformation from $y=\tan x$ to $y=5 \tan x$.
- Given original point $Q=(225^\circ,1)$ on $y=\tan x$.
- The transformation $y = 5 \tan x$ scales the $y$-values by 5.
- The $x$-coordinate remains the same: $225^\circ$.
- The new $y$-coordinate is $5 \times 1 = 5$.
So the new coordinates are $Q' = (225^\circ, 5)$.
3. Problem c: Find the new coordinates of point R after the transformation from $y=\tan x$ to $y=\tan(x - 5^\circ)$.
- Given original point $R = (-45^\circ, -1)$ on $y = \tan x$.
- The transformation shifts the graph right by $5^\circ$.
- To find new $x$, solve $x - 5^\circ = -45^\circ \Rightarrow x = -45^\circ + 5^\circ = -40^\circ$.
- The $y$-coordinate remains as $y = \tan(x - 5^\circ) = \tan -45^\circ = -1$.
So new coordinates are $R' = (-40^\circ, -1)$.
4. Problem d: Identify all points from the given set that lie on $g(x) = 3 \sin(2x) - 2$.
- The function is $g(x) = 3 \sin(2x) - 2$.
- We check each point:
(1) $x = \dfrac{\pi}{2}$:
$g(\dfrac{\pi}{2}) = 3 \sin(2 \times \dfrac{\pi}{2}) - 2 = 3 \sin(\pi) - 2 = 3 \times 0 - 2 = -2$ (does not match $y=1$)
(2) $x= \pi$:
$g(\pi) = 3 \sin(2\pi) - 2 = 0 - 2 = -2$ (does not match $y=4$ or $y=2$)
(3) $x = \dfrac{\pi}{4}$:
$g(\dfrac{\pi}{4}) = 3 \sin(2 \times \dfrac{\pi}{4}) - 2 = 3 \sin(\dfrac{\pi}{2}) - 2 = 3 \times 1 - 2 = 1$ (matches $y=-1$? No, value is 1, point says -1, so no)
(4) $x= \dfrac{3\pi}{4}$:
$g(\dfrac{3\pi}{4}) = 3 \sin(2 \times \dfrac{3\pi}{4}) - 2 = 3 \sin(\dfrac{3\pi}{2}) - 2 = 3 \times (-1) - 2 = -3 - 2 = -5$ (does not match $y=1$)
(5) $x= \pi$:
Same as before, $y=-2$.
None of the points match the exact $y$-values given, but problem states selected points that belong to the graph include (\frac{\pi}{2},1), (\pi,4), (\frac{\pi}{4},-1), (\frac{3\pi}{4},1), (\pi,2). Since none match $g(x)$ exactly, no points belong to the graph of $g(x) = 3 \sin(2x) - 2$.
Final Answer:
- a: $P' = (9^\circ,1)$
- b: $Q' = (225^\circ,5)$
- c: $R' = (-40^\circ,-1)$
- d: No points from the given set lie exactly on $g(x) = 3 \sin(2x) - 2$.