9Y1classpad

Vectors on the Classpad

The classpad uses a matrix notation for vectors.

This means that the vector 2**__i__** + 4**__j__** is represented on the calculator as **[2 4]**

To enter a vector, go to the **2D** tab, **CALC** section and select the single line matrix form.

To enter a 3-D vector, have the cursor inside the matrix **[ ]** then click on the single line matrix icon again.

If using the calculator, remember to write your answer back in normal __**i**__ and __**j**__ notation.

Polar Form To find the magnitude and direction of a vector, use the **toPol** function from the Action/Vector menu.

Set mode to Standard and enter:

toPol( [6 3] )

The result should appear as a magnitude (in surd form) first and the calculation for the angle second math \Big[ 3\sqrt{5} \quad \angle \big( \tan^{-1} \left( \frac{1}{2} \right) \big) \Big] math

Repeat with mode set to **Decimal** and **Degrees** and you should get: math \Big[ 6.71 \quad \angle \big( 26.57 \big) \Big] math

Rectangular Form

Given a magnitude and direction, to get a vector in the form **__v__** = x**__i__** + y**__j__**

Again, use the single line matrix form in **2D** tab, **CALC** section. The angle symbol is available in the **mth** tab, **OPTN** section. math \big[ 5 \; \angle 160 \big] math Just enter the matrix and hit EXE.

With the calculator in **Standard** mode, you will get: math \big[ 5 \centerdot \cos (160) \; 5 \centerdot \sin (160) \big] math

Change to **Decimal** mode and hit EXE again, and you will get: math \big[ -4.70 \; 1.71 \big] math This is equivalent to the vector: **__v__** = -4.70**__i__** + 1.71**__j__**

NB: The **toRect** function will do the same thing, but it is not needed.

Unit Vectors

Use the **unitV** function in the ACTION menu, VECTOR submenu.


 * unitV( [1 –3] )**

In **Standard** mode, this will give you an answer using surds. In **Decimal** mode, this will give you an answer using decimals.

Dot Product

Use the **dotP** function in the ACTION menu, VECTOR submenu


 * dotP( [3 4], [2 –2] )**

.