math.not.maths

When you take the square root of a fraction, it's like taking the square root of the numerator over the sqare root of the denominator.

The first one would be sqrt(17)/6.

The second would be sqrt(20)/9, except that sqrt(20) can be simplified to be 2*sqrt(5).

If it were 7x - 4x, you'd have 3x. Similarly, 7x^3/2 - 4x^3/2 = 3x^3/2.

I assume that by 0 you mean theta.

First you'd need to find the cosine of theta (because secant is the reciprocal of cosine). We can do this with right triangle trig. Sine is opposite over hypotenuse, so draw a right triangle, pick an angle and call it theta, and then lable the opposite side 17 and the hypotenuse 37. You can use the pythagorean theorem to get the measure of the third side.

17² + b² = 37²

289 + b² = 1369

b² = 1080

b = 6*sqrt(30)

The cosine of theta is 6*sqrt(30)/37. Therefore, the secant of theta is 37/6*sqrt(30). Apparently you're not supposed to leave radicals in the denominator of a fraction, so you'd multiply by sqrt(30)/sqrt(30) to get 37*sqrt(30)/6*30, which is 37*sqrt(30)/180.