How to use trignometric functions in the symbolic toolbox

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Muhammad Waqar 2013-10-10

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评论： Muhammad Waqar 2013-10-11

Hi!

I know that symbolic toolbox can evaluate the functions when the symbols are assigned their respective values however when i use the trignometric function, the evaluation comes as following rather than a number

e.g. Let J(thetha1,theta2,theta3) = sin(theta1 - theta2)/3 - cos(theta1 - theta3) - cos(theta1 - theta2) + sin(theta1 - theta3)/3;

now equating theta1,theta2 and theta3 values the answer comes out to be - cos(10) - cos(20) - sin(10)/3 - sin(20)/3

however when i type the above answer in the editor the value comes out to be 0.308. How can i solve this problem?

Thanks and regards, Muhammad Waqar Ahmed

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Answer 1

Walter Roberson 2013-10-10

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It is not clear which of the two you consider to be the problem.

If you want a floating point resolution of the formula, use double() on the symbolic formula.

Caution: cos(10) means cosine of 10 radians, not 10 degrees.

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Muhammad Waqar 2013-10-11

yes i want the answer to be numeric or floating point resolution as you said and yes i am aware that the angle is in radians for trignometric functions.

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