Question

value sin 75 is howmuch

Answer 1

Step-by-step explanation:

Well, we have to consider a few things.

1) The sign. As it's between 0 and 90, the sign is +. Good.

2) The value. We have that sin75=cos15 .

Now, we know the value of sin30 and cos30 , this suggests that we could use a half angle formula. We have that cos15=1+cos302−−−−−−√ , that is, 2+3√4−−−−√ . Or 2+3√√2 . Now the only thing that remains is turning that nested square root into something that is not nested, but I'm not exactly aware how that actually works I'm afraid.

EDIT: I will use for that "finishing touch". We have that 2+22−12−−−−−−√−−−−−−−−−−−√=2+12−−−√+2−12−−−√ , that is, 6√+2√2 . The final result to your problem would be that halved, that is, sin75=6√+2√4