Maths, Addmaths and Statistics: Post your doubts here!

[AhsanAfzal]

in part iv can we write answer without using graph??

 

[Ishrar Afrida]

in part iv can we write answer without using graph??

You can write no. (iv) without using graph.

 

[Saad Mughal]

Q.7 How to find x-co-ordinate of D?

y-coordinate of D = 8
Gradient AD = 4/x+5
Gradient BC = 4/-2 = -2
Since BC is the perpendicular bisector of AD,
Gradient AD = -1/Gradient BC
4/x+5 = -1/-2
4 = x+5/2
8 = x+5
x = 3

For E,
Equation of AE => 2y - x = 13
Equation of BC => y + 2x = 20
Solving Simultaneously gives us,
E = (5.4, 9.2).

 

[mohdumar]

Saad Mughal
In Linear Law questions, Do we always get the y-intercept from the graph, or can we also using (x,y) and gradient to get it?

 

[Anees2rehman]

Always frm the graph

 

[robinhoodmustafa]

Saad Mughal
In Linear Law questions, Do we always get the y-intercept from the graph, or can we also using (x,y) and gradient to get it?

You can either get the Y intercept by the "Coordinates" given on the line or use the Gradient and (x,y) to fine the "y=mx+c" equation ,Note "c" is the y intercept

 

[Saad Mughal]

Saad Mughal
In Linear Law questions, Do we always get the y-intercept from the graph, or can we also using (x,y) and gradient to get it?

You can use any of the two. It depends on how easy which method is to apply in the particular question.

 

[mohdumar]

You can use any of the two. It depends on how easy which method is to apply in the particular question.

Ok guys.

 

[Saad Mughal]

Just hoping that Linear law GRAPHS don't come. They can be so tedious and error-prone sometimes.

 

[mohdumar]

Just hoping that Linear law GRAPHS don't come. They can be so tedious and error-prone sometimes.

Yeah, something like find eq from given drawn graph would be nice.

 

[Saad Mughal]

Yeah. The graph should be drawn/given.

 

[Talha Irfan]

find unit vector in direction 3i+4j
then multiply it with speed 20kph to get velocity vector

ok, but why you finding unit vector was not velocity vector = speed x direction (which is given)

 

[Talha Irfan]

what is the area of trapezium?

A more easier and effective way is to use heron's formula for calculating area, its perhaps the most easiest method.

 

[AhsanAfzal]

can any1 answer part iii?

 

[redd]

I did the same. But I don't get the logic of the multiplication.
The direction and Cartesian plane method is more logical.

In this question we have to first calculate the angle for 3i and 4j as tan(inverse) 4 divided by3. we'll get the velocity vector this way and then we'll multiply iit with t to getits position.

 

[Saad Mughal]

In this question we have to first calculate the angle for 3i and 4j as tan(inverse) 4 divided by3. we'll get the velocity vector this way and then we'll multiply iit with t to getits position.

I know that and I'm saying that this is the proper and logical method of doing this.
In the other method, where we calculate the unit vector of the direction and multiply by the speed to get the velocity vector is illogical.

 

[redd]

I know that and I'm saying that this is the proper and logical method of doing this.
In the other method, where we calculate the unit vector of the direction and multiply by the speed to get the velocity vector is illogical.

well, i never knew the other method so how did it go today?

 

[redd]

I know that and I'm saying that this is the proper and logical method of doing this.
In the other method, where we calculate the unit vector of the direction and multiply by the speed to get the velocity vector is illogical.

well, i never knew the other method so how did it go today?

 

[Saad Mughal]

well, i never knew the other method so how did it go today?

Good ALHUMDULILLAH.

 

[Suchal Riaz]

I did the same. But I don't get the logic of the multiplication.
The direction and Cartesian plane method is more logical.

These vectors ae just unut vectors which show direction. We need to find vector. Thats why we multiply so magnitude of vector is same as the magnitude given.