Show that the area of a triangle with sides a and b and with an included angle θ is A=(1/2)*a*b*sin(θ)

[MentholMan]

This is the problem I'm working on and I'm not sure how to set up this question or if my work is valid



This is what I have, I'm not sure if what I'm doing with the first attempt is valid and I know the seconded attempt is too basic. I would like some help on how to start this question

 

[blamocur]

Why do you think that it isn't valid?

 

[MentholMan]

Its from the trigonmetry appendix of James Stewart Calculus 7th Edition. I kinda figured they'd want more.

 

[The Highlander]

This is the problem I'm working on and I'm not sure how to set up this question or if my work is valid
View attachment 35486


This is what I have, I'm not sure if what I'm doing with the first attempt is valid and I know the seconded attempt is too basic. I would like some help on how to start this question

View attachment 35487

Your second attempt is "textbook". ?
(Look in one and you will see. ?)

 

[The Highlander]

Its from the trigonmetry appendix of James Stewart Calculus 7th Edition. I kinda figured they'd want more.

Why would they "want more"?
You've done exactly what the question asked: " Show that the area of the triangle...".

 

[Dr.Peterson]

This is the problem I'm working on and I'm not sure how to set up this question or if my work is valid
View attachment 35486


This is what I have, I'm not sure if what I'm doing with the first attempt is valid and I know the seconded attempt is too basic. I would like some help on how to start this question

View attachment 35487

The first attempt says nothing about theta or the area, and works out c, which is not needed; so although nothing there is really invalid, it is irrelevant.

The second is appropriately basic! Perhaps some words could be added, but nothing more is really needed.