SAT (Fall 2023)
- Solving quadratic equations — Basic example
- Solving quadratic equations — Harder example
- Interpreting nonlinear expressions — Basic example
- Interpreting nonlinear expressions — Harder example
- Quadratic and exponential word problems — Basic example
- Quadratic and exponential word problems — Harder example
- Manipulating quadratic and exponential expressions — Basic example
- Manipulating quadratic and exponential expressions — Harder example
- Radicals and rational exponents — Basic example
- Radicals and rational exponents — Harder example
- Radical and rational equations — Basic example
- Radical and rational equations — Harder example
- Operations with rational expressions — Basic example
- Operations with rational expressions — Harder example
- Operations with polynomials — Basic example
- Operations with polynomials — Harder example
- Polynomial factors and graphs — Basic example
- Polynomial factors and graphs — Harder example
- Nonlinear equation graphs — Basic example
- Nonlinear equation graphs — Harder example
- Linear and quadratic systems — Basic example
- Linear and quadratic systems — Harder example
- Structure in expressions — Basic example
- Structure in expressions — Harder example
- Isolating quantities — Basic example
- Isolating quantities — Harder example
- Function notation — Basic example
- Function notation — Harder example
Watch Sal work through a basic Interpreting nonlinear expressions problem.
Want to join the conversation?
- Since the SAT is timed, would it be wiser to use his second method rather than first because it saves time?(60 votes)
- Yes, Sal explains multiple methods to solve the problems and you would pick the one you prefer the most.(45 votes)
- Ain't there shortcut methods. Khan academy solves questions in a way that it consumes lots of time.(37 votes)
- I still don't get why he multiplied it by the 10^6 to the 0.75. Please explain.(4 votes)
- One question. All these topics could be either in the section with calculator or that without? So you have to know how to do them without calc? Are there exceptions?(8 votes)
- what do -4.9t^2 and 8t represent?(3 votes)
- If you've taken a physics class before, one of the kinematic equations is Δx = V_0*t + 1/2 at^2. This relates the change in position to an initial velocity and an acceleration. For a projectile (like the basketball thrown up into the air), the acceleration would be the force of gravity, or 9.8 m/s^2. The initial velocity is what the ball has because of being thrown upwards. The displacement can be broken down to the difference between the projectile's height (h(t)), and an initial height (1.2). We can then modify the equation to look like what you have in the question:
Δx = V_0*t + 1/2at^2
h(t) - h_0 = 8t + 1/2 (-9.8)t^2
h(t) = -4.9t^2 + 8t + 1.2
Of course, you don't need to know where any equation that you see on the SAT comes from in order to answer the question correctly.(5 votes)
- Simple elimination would solve this question in about 15 seconds.
A wouldn't work because the metabolic rate of the elephant is greater than that of the mouse.
B wouldn't work for the same reason, as it is stating the mouse's metabolic rate is faster.
C is possible, as the elephant's metabolism is stated to be faster.
D wouldn't work, as the base body mass is multiplied by an exponent and the final value will not be in the same proportions.(2 votes)
- Nice logic! Unfortunately, not everybody will be able to narrow down a question to one answer just like that, and almost no one would be able to do so for every question, which is why the video exists. But doing great on the SAT is really all about finding these shortcuts that allow you to choose answers quickly and with certainty.(4 votes)
- [Instructor] We're told the function above models the height h, in meters, of a basketball above ground t seconds after being thrown straight up in the air. What does the number 1.2 represent in the function? So pause this video and think about it on your own before we work through it together. All right, so we could just visualize what's happening when you throw a basketball straight up in the air. This is the ground. Let's say this is the person throwing the basketball. This is the basketball. It starts at some height. So whatever height this is, that's its initial height at t equals zero. And then, it's gonna be thrown with some upward velocity. And it's initially going to be a high velocity, but then it's gonna slow down. And then, at some point, it's gonna be stationary, and then it's gonna start accelerating back downwards. Now, as I mentioned, at t equals zero, what do we see over here? Well, let's see, h of zero is going to be equal to, this term goes away, 'cause anything times zero is zero. That term goes away. And we're just left with 1.2, the exact number that they're thinking about. So if you think about it, h of zero, this tells you the position of the ball, in terms of meters above the ground, right when we are starting. So it's telling us the initial height of the ball. So let's see, it looks like that's exactly what they're saying for choice A, the initial height, in meters, of the basketball. The maximum height in meters of the basketball? No, that's definitely not saying that. The maximum height is not going to occur at t equals zero. It's going to occur sometime after that. Rule that one out. The amount of time in seconds the basketball remains airborne. No, that's not the case. Any value that h takes on, remember, h is in meters. T, which is an input into the function, is time. So if you're talking about something that h is equal to, which, in this case, h is equal to 1.2 and t is equal to zero, you're talking about a height above the ground. And then the initial speed. Well, once again, no, this is h of zero, which is the height above the ground. So we like choice A.