, how do i calulate this to get 0.46??? if
(Note: The exact value of each trig function should be known to you but are not required if an approximate answer is asked for).
I have no idea why you would be trying to re-write the expression.
No, it's nothing like that. since , . You square the entire function, not just "x".
mr fantastic suggested that you put the numbers into a calculator. Is the problem that your calculator does not have a "sec" key? If so then means that you can use the "cos" key followed by the "1/x" key:
If then cos(x)= 0.70710678118654752440084436210485 and the reciprocal (1/x) of that is 1.4142135623730950488016887242097. Pressing the " " key now gives 2. That should be no surprise. One of the "standard" values of cosine you should memorize is . Inverting that gives and, squaring, 2.
Of course, since , also so that . .
Now, what is ? What is ?