Subjects analytic geometry

Check Work Cec80C

Step-by-step solutions with LaTeX - clean, fast, and student-friendly.

Use the AI math solver

1. **Stating the problem:** You ask whether everything in the work shown is totally correct. 2. **Formula used for this type of problem:** For a line through a point $A(x_A,y_A)$ with direction vector $\vec{v}=(p,q)$, a parametric form is $$x=x_A+kp,\ y=y_A+kq$$ with $k\in\mathbb{R}$. 3. **Important rule:** To check whether a point lies on a line, substitute the coordinates into both equations and see whether the same parameter value works. 4. **Checking the first visible line pair:** For $r: x=3+2k,\ y=-1+3k$ and $s: x=3+4k,\ y=1+6k$, the direction vectors are $(2,3)$ and $(4,6)$. 5. **Simplifying the direction vectors:** $$\frac{2}{4}=\frac{1}{2},\ \frac{3}{6}=\frac{1}{2}$$ so the lines are parallel. 6. **Checking if they are the same line:** A point on $r$ is $(3,-1)$ when $k=0$. For $s$, to get $x=3$ we have $$3=3+4k$$ so $$0=4k$$ and $$k=0$$. 7. **Now test the $y$-value with cancellation shown:** $$-1\neq 1+6\cdot 0=1$$ so the point from $r$ is not on $s$. 8. **Conclusion for that pair:** The lines are parallel but not coincident. 9. **Checking the line through $A(6,6)$ and $B(2,8)$:** The direction vector is $$\vec{AB}=(2-6,\ 8-6)=(-4,2)$$ so a parametric form is $$x=6-4k,\ y=6+2k.$$ 10. **Checking point $P(-6,12)$:** Substitute into $x=6-4k$: $$-6=6-4k$$ $$-12=-4k$$ $$\frac{-12}{-4}=\frac{\cancel{-12}}{\cancel{-4}}=3$$ so $k=3$. 11. **Verify in the $y$-equation:** $$y=6+2\cdot 3=12$$ so $P$ is on the line. 12. **Conclusion for this part:** Yes, that part is correct. 13. **Checking the Cartesian equation from $x=3k-1,\ y=4-6k$:** From $x=3k-1$, we get $$x+1=3k$$ $$\frac{x+1}{3}=k$$ with the canceled factor step $$\frac{x+1}{\cancel{3}}=k$$ not being the cleanest form, so the correct substitution is better written as $$k=\frac{x+1}{3}.$$ 14. **Substitute into $y$:** $$y=4-6\cdot \frac{x+1}{3}$$ $$y=4-2(x+1)$$ $$y=4-2x-2$$ $$y=-2x+2$$ so the Cartesian equation is $$2x+y-2=0.$$ 15. **Conclusion for that part:** Yes, the final equation is correct. 16. **Checking the line through $T(1,2), A(3,3), C(-4,0), K(-4,3)$:** The vector calculations are correct: $$\vec{AT}=(1-3,2-3)=(-2,-1),$$ $$\vec{AK}=(-4-3,3-3)=(-7,0),$$ $$\vec{TK}=(-4-1,3-2)=(-5,1),$$ $$\vec{KC}=(-4+4,0-3)=(0,-3).$$ 17. **Important correction:** In the parametric forms, the base point must match the line chosen, so the forms should be written consistently as $$AT: x=3-2k,\ y=3-k,$$ $$AK: x=3-7k,\ y=3,$$ $$TK: x=1-5k,\ y=2+k,$$ $$KC: x=-4,\ y=3-3k.$$ 18. **Conclusion for that part:** The vectors are correct, and the parameter equations are essentially correct, but the generic template was written a bit sloppily. 19. **Checking the parameter values on line $AB$ with $A=(5,3)$ and $\vec{AB}=(4,2)$:** The coordinate formula is $$P=A+k\vec{AB}.$$ 20. **Example for $k=2$ with cancellation shown:** $$P=(5,3)+2\cdot(4,2)=(5,3)+(8,4)=(13,7).$$ 21. **Checking the other values:** $$Q=(5,3)+(-1)(4,2)=(1,1),$$ $$R=(5,3)+(-2)(4,2)=(-3,-1),$$ $$S=(5,3)+\frac{3}{2}(4,2)=(11,6),$$ $$T=(5,3)+\frac{1}{2}(4,2)=(7,4).$$ 22. **Important correction:** The last one was written incorrectly in the work shown; it should be $(7,4)$, not $(3,2)$. 23. **Final conclusion:** Not everything is totally correct. Several parts are correct, but there is at least one clear mistake in the last parameter point, and some line-parameter notation is a bit inconsistent.