What is the significance of Vt la and cos thetaSolutionVt th

What is the significance of Vt, la, and cos theta?

Solution

V(t) that is what you mean is a function of time-dependent voltage, ie for different times there is a different voltage value.

in that equation you saw (a) means the extent of your function.

cos (thetaT) in tun voltage function here aparace this means that your source is sinusoid and the argument that accompanies the T is the angular frequency in which they work. (W = theta)

in such a case than this that questions about the cosine:

trigonometry, cosine (cos abbreviated) of an acute angle in a right triangle is defined as the ratio between the adjacent said leg angle and the hypotenuse