How to find maximum & minimum value of expressions like 2sinx-5 , 3cosx+4.Plzz xplain..!!

Hi Ranjita,

To find the maximum value of expressions with Trigonometric Functions, you have to find the value of that Trigonometric Function for which the expression attains its max value.

In the expressions you have mentioned, clearly the expressions are maximum when sinx=1 and cosx=1 respectively.

Always remember sinx lies in [1,1] and cosx also lies in [1,1].

The respective max values of the expressions would be -3 and 7.

Regards,

Ashwin (IIT Madras).

how this so , that sinx lies in(1,1) & cos also..??

and what are the minimum values...??

Hi Ranjita,

sinx and cosx are trigonometric functions whose range is [-1,1]

Sorry that should have been -1 to 1. I had typed it wrongly previously.

So minimum value would be -1 and maximum value would be 1.

Regards,

Ashwin (IIT Madras).

And hence the minimum values of the expression would be = -2-5 and -3+4, ie -7 and 1 respectively.

Hope now its clear.

Regards,

Ashwin (IIT Madras).