SAT Desmos Command Sheet: Entries, Checks and Common Errors

Enter:

2x+y=11
x-y=1

Checked result: Intersection (4,3). The original equations give 11 and 1.

Watch for: Read the requested coordinate or combination; an intersection is a pair, not automatically the final answer.

Enter:

y=x^2-6x+5

Checked result: Zeros at x=1 and x=5; vertex (3,-4).

Watch for: Zeros are x-values at y=0. The vertex is a different quantity.

Enter:

f(x)=2x^2-3x+1
f(4)

Checked result: f(4)=21.

Watch for: Use parentheses for a negative input, and respect any problem domain.

Enter:

y=x^2
y=2x+8

Checked result: Intersections (-2,4) and (4,16).

Watch for: Zoom out to find both intersections. Check both original equations.

Enter:

Table x_1: 1,2,3,4
Table y_1: 9,13,17,21
y_1~m x_1+b

Checked result: For this exact table m=4 and b=5. A prediction at x=6 is 29.

Watch for: Use ~ for fitting a model and = for defining it. A fitted prediction is not a newly observed data point.

Enter:

f(x)=-2(x-4)^2+30
f(0)
f(2)

Checked result: On 0<=x<=2, the maximum is 22 at x=2, not the unrestricted vertex value 30.

Watch for: A graph alone does not remove restrictions. Check endpoints and whether the vertex lies in the allowed interval.

Enter:

sin(30) in degree mode

Checked result: 1/2 in degree mode.

Watch for: Use the mode appropriate to the stated angle units. The same numeric input in radians has a different meaning.

Enter:

y=x+100
y=2x

Checked result: Intersection (100,200).

Watch for: Change the graph window when the needed values are outside it. A missing visible intersection is not proof of no solution.