Evaluate: 4tan^2 135degrees + 5sin^2 120degrees-cos^2 180degrees

Answer 1

tan(135) = -1

So tan²(135) = (-1)² = 1

and 4 tan²(135) = 4 * 1 = 4

sin(120) = √3/2

sin²(120) =( √3/2)² = 3/4

5 sin²(120) = 5 * 3/4 = 15/4

cos(180) = -1

cos²(180) = (-1)² = 1

Now put all those terms together:

4 + 15/4 - 1 = 3 + 15/4 = 12/4 + 15/4 = 27/4 = 6.75