[talanum1 (OP)]

At the Lagrange point L2 the Earth and Sun's gravity cancels. Does it mean the Sun's gravity goes negative here? Why isn't the force on Mars, Jupiter etc. repulsive?

[talanum1 (OP)]

Don't bother answering. The answer is that the gravity vectors of the Earth and Sun is in opposite directions and equal at L2.

[talanum1 (OP)]

On second thought: the gravity vectors should be in the same direction at L2.

[Eternal Student]

Hi.

On second thought: the gravity vectors should be in the same direction at L2.

   Yes they are.   They don't cancel, they sum.
    A Lagrange point isn't a place where a satellite would feel no force due to gravity, it would certainly feel a gravitational force.   However, that force would be just right to keep the satellite moving in circular motion in a way that matches the rotation rate of the earth around the sun.    It's only from the planet earth that the satellite seems to be stationary.
   See https://solarsystem.nasa.gov/resources/754/what-is-a-lagrange-point/   for more information.

Best Wishes.