# Thread: can i say this is true?

1. ## can i say this is true?

ok i have a problem that im working on and i want to know if i can say the relationship between theta, theta 1 and theta 2 is true? well here is attachment of the problem. basically they want me to find PR such that 0< PR<3 and m<theta is a maximum. so this means im gonna to take the derivative and set equal to zero. well take a look at my work and let me know if im on track or clueless. thanks in advance.maximize the angle.pdf

2. Originally Posted by slapmaxwell1
ok i have a problem that im working on and i want to know if i can say the relationship between theta, theta 1 and theta 2 is true? well here is attachment of the problem. basically they want me to find PR such that 0< PR<3 and m<theta is a maximum. so this means im gonna to take the derivative and set equal to zero. well take a look at my work and let me know if im on track or clueless. thanks in advance.maximize the angle.pdf
sorry, you cannot say that $\displaystyle \theta = \theta_1 + \theta_2$

however, you can say that $\displaystyle \theta + \theta_1 + \theta_2 = \pi$

so ...

$\displaystyle \theta_1 + \theta_2 = \pi - \theta$

$\displaystyle \arctan\left(\frac{2}{R}\right) + \arctan\left(\frac{5}{3-R}\right) = \pi - \theta$

find $\displaystyle \frac{d\theta}{dR}$

... you sure about finding $\displaystyle R$ such that $\displaystyle \theta$ is a minimum ?

3. thanks and yes i want to find the maximum...