Solve 2 equations

[kenan2]

Hi.

How can I solve for this ?

[ttokoro]

Solved.

[Werner_E · Accepted solution]

Here's an alternative solution.

Worksheet in P4 format attached

[kenan2]

Need help again......

I need solve 2 equations again

[Werner_E]

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@kenan2 wrote:

Need help again......

I need solve 2 equations again

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Similar to the system we solved before.

You have to solve for both unknowns.

Its sometimes necessary to set the labels for the variables by hand as Primes autolabeling very often fails.

Here is a solution without using the symbolics. We can use a numeric solve block as all the other of your variables have been assigned numeric values.

This solve block was less sensible wrt the labels of the variables.

Worksheet in MP4 format attached

[kenan2]

Again.... Hate theres 2 equations...

[Werner_E]

Where is the problem? I don't see your attempt solving this system.

Whenever you have two equations in two variables (here v.f and theta) you have to solve for both of them, even though you might be just interested in one.

Because of the units applied I would suggest you use a solve block as shown in one of your questions before .

The symbolics does not know anything about units and always tries to return a complete solution. So sometimes it might be necessary to tell Prime (with "assume" modifier) that m, s and kg are non-zero reals or you will have to provide a range for theta (possibly 0<theta<pi/2).

[Fred_Kohlhepp]

This is a job for vector analysis.  Vf = 9.677 m/s

[kenan2]

@Fred_Kohlhepp how have you get that (see upload).

[LucMeekes]

Like this:

Success!
Luc

[Fred_Kohlhepp]

Luc's answer is the same and neater.

[ttokoro]