
Haven't tried it, but look at this:
https://answers.yahoo.com/question/index?qid=20150724191938AAydOpZ
sure looks messy, I am sure there is an easier wayposted by Reiny

100+70 = 10
Adding 'tan' on both sides,
tan(100+70)= tan10
(tan100+tan70)/1tan100.tan70 = tan10
Multiplying 1tan100.tan70 with tan10,
tan100+ tan70= tan10+tan10.tan100.tan70
tan10+tan100+tan70= tan10.tan70.tan100 provedposted by Saloni
Respond to this Question
Similar Questions

trig
a plane is flying at an altitude of x with the distance at 800 meters with an angle of 70 degress. what equation would you use to solve. tan70= x/800 tan70= 800/x sin70= x/800 
trig
prove that :tan20 tan30 tan40 =tan10 
campridge trigonometry
prove that ; tan20 . tan30 . tan40 = tan10 
PreCalculus
I need help on these problems they are from my study guide and i don't have a clue on how to do these 3 problems and if anyone can show the steps and somewhat explain the steps so i can do it myself next time. 1.) 
math
calculate the value of (1 sec20¡ã cot20¡ã)(1cosec20¡ã tan70¡ã) 
maths
Tan100+4sin100=? As tan(90+10)+4sin(90+10) cot10+4cos10 Aftr that i don't know what to do 
Math
Solve without the use of a calculator: sin20(tan10+cot10) I know it should equal two but I don't know how to get there 
trig
tan200(cot10tan10) 
trig
tan200(cot10tan10) 
Geometry
Without using a calculator compare the values of tan60 and tan70. Explain your reasoning.