how to find the maximum of (2 sin(theta)^2 *cos(phi)^2) using matlab?

how to find the maximum value of (2 sin(theta)^2 *cos(phi)^2) using matlab? and also similar trigonometric functions in matlab

[Fangjun Jiang]

Well, without any constraint, I would say it is 2!

Answer 1

[Walter Roberson]

As you have not restricted the range:

The minimum and maximum of the sin() and cos() functions are -1 and +1. In your expression they are both squared so the maximum values will be (-1)^2 and (+1)^2, which is +1 . Multiply two such independent maximum together gives +1 * +1 = +1 . Multiply that by 2 gives a maximum value of +2 .

The code to find the maximum is then

2 * 1 * 1

The difficulty of finding the maximum of other trig expressions depends greatly on what operators are allowed and what other functions are allowed.

[yashaswi]

its not the multiplication sign...n i understand it when u say 2*1*1...but achieving the same using functions in matlab to find the maximum of trigonometric function..i have spent the whole day trying to achieve this n i feel sick n tried

[yashaswi]

hey!!! it worked..separating each function...!thanx a lot!!

Answer 2

[Wayne King]

Just use max()

[yashaswi]

well,i have tried..i have really been successful..could you show me how i could do it?? i always get an error??

[Walter Roberson]

That's because you need a multiplication sign between the "2" and the rest of the expression.