A level maths help

1. prove that sec^4theta - tan^4theta = sec^2theta+tan
^2theta

2. hence solve the interval -180deg < theta<180deg, sec^4theta = tan^4theta+3tantheta

I have the answer for part 1 i just need part 2

(edited 2 months ago)

Reply 1

mqb2766

Original post by cheery-condition

1. prove that sec^4theta - tan^4theta = sec^2theta+tan
^2theta

2. hence solve the interval -180deg < theta<180deg, sec^4theta = tan^4theta+3tantheta

I have the answer for part 1 i just need part 2

Looks like youd just use the first part and note you can use the pythagorean identity for sec^2 to end up with an equation in tan which can be solved.

Reply 2

Muttley79

Original post by cheery-condition

1. prove that sec^4theta - tan^4theta = sec^2theta+tan
^2theta

2. hence solve the interval -180deg < theta<180deg, sec^4theta = tan^4theta+3tantheta

I have the answer for part 1 i just need part 2