How do you simplify cos(sin^-1(3/5)-cos^-1(1/2))cos(sin1(35)cos1(12))?

1 Answer
May 13, 2016

(1/10)(+-4+-3sqrt3)(110)(±4±33)

Explanation:

Let a = sin^(-1)(3/5) and b = cos ^(-1)(1/2)a=sin1(35)andb=cos1(12).

Then, sin a = 3/5, cos a = +-4/5, cos b = 1/2 and sin b = +-sqrt3 /2sina=35,cosa=±45,cosb=12andsinb=±32

Now, the given expression is cos (a - b )cos(ab)

= cos a cos b + sin a sinb=cosacosb+sinasinb

=+-2/5+-3sqrt3/10=(1/10)(+-4+-3sqrt3)=±25±3310=(110)(±4±33).

The choice of sign depends on the specified ranges (if any ), for the inverse angles.a and b.