Question

Trigonometry Prove SinA/1+cosA + TanA = SecA
.. Do it fast​

Answer 1

Answer:

Let’s see. We can start by writing it out, and then manipulating each side to make them equal.

sinA∗tanA+cosA=secA

I usually convert things to sin and cos just to make it more familiar.

sinA∗sinAcosA+cosA=1cosA

Now you can reduce the fraction on the left.

sin2AcosA+cosA=1cosA

Now you can manipulate cosA to get a common denominator

sin2AcosA+cos2AcosA=1cosA

Now that you have a common denominator, you can combine the fractions.

sin2A+cos2AcosA=1cosA

And now since you (should) know that sin2A+cos2A=1, you can substitute that expression for 1, leaving you with:

1cosA=1cosA