Vectors (Multiplication)

[Muhammad Danish]

Homework Statement

Homework Equations

Is my solution correct? If not then please point out the mistakes and help me solve this question in the right way. Thanks in advance.

The Attempt at a Solution

 

[.Scott]

|a| = |b| |h|
so
|h| = |a| / |b|
and h<0

 

[Muhammad Danish]

|a| = |b| |h|
so
|h| = |a| / |b|
and h<0

After finding h, can we solve this question by matrix method? (The way I did)

 

[.Scott]

You have h = -|b|/|a|.
It should be h = -|a|/|b|.

Then solve with b = a/h

 

[Muhammad Danish]

You have h = -|b|/|a|.
It should be h = -|a|/|b|.

Then solve with b = a/h

If we make |h| the subject, it will be |h|= |a| / |b|. The answer will be positive. So | | signs will reverse the signs and give a negative value of h?

 

[.Scott]

Right. We need to make h negative.
|a|/|b| is positive over positive, which is positive.

Per the problem, we need h to be negative...
So, h = -|a|/|b|

 

[Muhammad Danish]

Right. We need to make h negative.
|a|/|b| is positive over positive, which is positive.

Per the problem, we need h to be negative...
So, h = -|a|/|b|

How will it become negative?

If I use the equation |a| = |h| |b| then how can I get a negative value of h?

 

[.Scott]

How will it become negative?

If I use the equation |a| = |h| |b| then how can I get a negative value of h?

By using the equation: h = -|a|/|b|

Here's the sequence:
|a| = |h| |b|
|a|/|b| = |h|
so either h = |a|/|b|
or h = -|a|/|b|

But we know from the problem statement that it must be negative.

 

[Muhammad Danish]

By using the equation: h = -|a|/|b|

By removing ''| |'' from h, the other side will become negative?

 

[.Scott]

By removing ''| |'' from h, the other side will become negative?

I added some text to my last post.
Here it is again:

Here's the whole sequence:
|a| = |h| |b|
|a|/|b| = |h|
so either h = |a|/|b|
or h = -|a|/|b|

But we know from the problem statement that it must be negative.

 

[Muhammad Danish]

I added some text to my last post.
Here it is again:

Here's the whole sequence:
|a| = |h| |b|
|a|/|b| = |h|
so either h = |a|/|b|
or h = -|a|/|b|

But we know from the problem statement that it must be negative.

Like this?

 

[.Scott]

Yes!!

 

[Muhammad Danish]

Yes!!

Thank you!!!!

 

[Ray Vickson]

Homework Statement

View attachment 227388

Homework Equations

Is my solution correct? If not then please point out the mistakes and help me solve this question in the right way. Thanks in advance.

The Attempt at a Solution

View attachment 227389

Your problem is totally unreadable. Please take the trouble to adhere to the PF standard, by typing out the statement of the problem. If you cannot do that, you should at least make sure you take a proper photo that will come out readable by the rest of the world.