write the polar eqaution

Question

3 = r cos (theta - 315)
in rectangular form.

Answer 1

3=r cos(a-315)
where theta=a
now 315=360-45=2pi-pi/4=-pi/4
therefore, -315=+pi/4
therefore,3=r cos(a-315)becomes
3=r cos(a+pi/4)
but cos(a+pi/4)= cosa*cospi/4 - sina*sinpi/4

Answer 2

3=r cos(a-315)
where theta=a
now 315=360-45=2pi-pi/4=-pi/4
therefore, -315=+pi/4
therefore,3=r cos(a-315)becomes
3=r cos(a+pi/4)
but cos(a+pi/4)= cosa*cospi/4 - sina*sinpi/4
= 1/root2(cosa-sina)
3= 1/root2(rcosa-rsina)
= 1/root2 (x-y)
3root2=x-y
y = x-3root2 is an equation of line